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What's your opinion on mandatory military service? (lemm.ee)

submitted 1 day ago* (last edited 1 day ago) by helloworld55@lemm.ee to c/asklemmy@lemmy.world

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This question was inspired by a post on lemmy.zip about lowering the minimum age to purchase firearms in the US, and a lot of commeters brought up military service and training as a benchmark to normal civilians, and how if guns would be prevalent, then firearm training should be more common.

For reference, I live in the USA, where the minimum age to join the military is 18, but joining is, for the most part, optional. I also know some friends that have gone through the military, mostly for college benefits, and it has really messed them up. However, I have also met some friends from south korea, where I understand military service is mandatory before starting a more normal career. From what I've heard, military service was treated more as a trade school, because they were never deployed, in comparison to American troops.

I just wanted to know what the broader Lemmy community thought about mandatory military service is, especially from viewpoints outside the US.

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[–] tal@lemmy.today 5 points 1 day ago* (last edited 1 day ago) (1 children)

So, usually when you have mandatory military service, the point is to make everyone go through training, so that if they have to call people up, they immediately have a large pool of people who have at least some idea of what they're doing (though they're probably a bit rusty).

The US has never done that. A number of countries have. Why?

A big factor here is geography.

The primary scenario you're going to need a lot of infantry on very short notice is if you're being invaded. If a country might find itself in a situation where soldiers are massing at their border and about to cross it, they cannot screw around for months calling people up and training them.

This mostly isn't a problem for the US, because of its geography and military position. The US is sitting on a landmass consisting of two continents with no other major powers. That makes it hard for a neighbor to invade -- you have to move an invasion force across the ocean. To do that, you have to gain control of the oceans so that you can move transports across them, which is extremely difficult against the US: it's the largest air and naval power in the world, and on top of that, it's allied with a large percentage of the remaining air and naval powers.

Here's a decade-old article that has someone from Jane's talking about what would be involved in an invasion of the mainland US in a worst-case scenario, where literally the rest of the world is conducting an invasion:

https://www.vice.com/el/article/we-asked-a-military-expert-if-the-whole-world-could-conquer-the-united-states/

We Asked a Military Expert if All the World’s Armies Could Shut Down the US

But can we get them? Is that even an option, or are they really harder than China, Russia, Iran, the UK, France, Germany, Iceland, Belarus, and every other country put together? In order to find out just how possible a Rest of the World versus America revenge fantasy invasion would be, I got in touch with Dylan Lehrke, Americas Armed Forces Analyst at IHS Jane’s.

ICE: First thing’s first. How could the rest of the world disable the US nuclear capacity?

Dylan Lehrke: It is virtually impossible to eliminate the US nuclear arsenal since it is based on a triad of land, air, and sea delivery systems designed to provide a counterstrike capability. The submarine-launched ballistic missiles in particular are widely accepted as the most survivable element of the US nuclear deterrent as a portion of it is always at sea. The land-based missiles too are difficult to eliminate, as they are in hardened silos in the middle of the country. Any adversary facing the United States would need to either be willing to absorb a nuclear attack or develop a ballistic-missile defense system currently beyond the scope of anything technologically feasible.

Well, I’ve got a pretty good blueprint of one in my bedroom, so let’s assume it’s totally possible. If not, perhaps we need to go to the source: Obama. Could the nuclear football be grabbed from the president?

I can’t really answer this one since we have very little information on the technical aspects.

OK. Let’s just assume the technical aspects are that he carries it around in his pocket and I’ve stolen it. So, once the nuclear capabilities are down, what could an invasion of the US look like?

The US is the sole country in the world that has the capability to project force across the globe on a large scale. The combined military air- and sealift capability of the rest of the world would be insufficient to even get a foothold on the continental United States. The amphibious assault capability of the world’s militaries, excluding the United States, is simply too small.

That means the adversary would have to seize and use civilian aircraft and ships not designed for nonpermissive environments. These ships would require secure bases in Canada and Mexico, since they lack the capability to deliver forces onto unimproved shores. Thus, any attempted invasion of the US would first look like a rather motley caravan of vulnerable civilian ships and aircraft.

If these forces managed to avoid US attacks and build up, they could then launch an attack over land.

I’m sure we could manage it. Where would an invasion begin? Which parts of the American coast are most vulnerable to attack?

As I already noted, the amphibious-assault capability of the combined militaries of the world are simply too insignificant to get a beachhead on a coast. If they managed to go undetected, itself an impossible feat in light of modern surveillance capability, they still could not build up a force of any size before being pushed back into the sea.

Thus, an invasion would have to come via a land border, with the terrain of the southern border (that with Mexico) being most conducive to military operations. However, the fact that the largest US Army armor base happens to be in Texas naturally would hinder such an attack. Going through the Canadian border—out West, to avoid the Great Lakes and St Lawrence Seaway—would be easier, although the invasion would then be limited to light infantry and would have trouble concentrating forces. In addition, it would fail to take over population centers or other important strategic points, since it is mostly national parks out there.

Well, once we have the national parks, we have the bears and wolves on our side, which will make us unbeatable. I guess the big question here is: Are the world’s combined forces—including those mad North Koreans, because every little helps—enough to defeat those of the US?

Yes, but only if the US is on the offensive or only if defeat does not equate to conquer or destroy, which it generally does not. The world could, for example, certainly contain the US as the US did the Soviet Union. But the question you are really asking, if I am correct, is: Are the world’s combined forces enough to conquer the United States? Here the answer is no, for it is much harder to project force. It requires logistical resources that the rest of the world simply does not have.

OK. That’s disappointing.

The primary problem here is geography. Just as the vast Russian steppe swallows armies, so would the oceans that surround the US. No matter the manpower or armament, it must be delivered across the Pacific and Atlantic in order to be brought to bear. This is where US naval and air power would destroy any adversary, far before they sullied the US shore.

And this is where you meet the second primary problem, which is technology. There are not enough aircraft carriers and amphibious warfare ships in the combined navies of the world to force an entry past the US Navy. There are not enough attack fighters to gain air superiority against the US Air Force. This is how amazingly out of balance the military might of the world is today.

Could we find a work-around?

The solution for the invading world armies would be to negate the importance of geography and technology. This means not relying on armies and navies and air forces but instead targeting the US in the space and cyber domains. By defeating US satellites and attacking US networks, one bypasses geography and eliminates technology, both that of the military and within the industrial base that is at the core of that military might.

Cool, so we’ll just get the hackers onboard.

However, one still does not conquer the soil. So we arrive at the same conclusion: as the world military balance stands today, even in the unlikely case that the entire world aligns against them, the United States could not be conquered. It can only be defeated. I suspect you had hoped for a more Red Dawn-type possibility but I can’t offer one without stretching reality beyond the point of reason. We would have to bring in pure science fiction to make it feasible.

Oh well, I guess that’s pretty emphatic. Thanks for humoring me, Dylan.

Up until, say, about World War II, air forces weren't a major factor, and the naval balance of power meant that the US was not the largest naval power in the world. Around World War I, it was a second-tier naval power, well behind Germany and the British Empire. It was possible for larger naval powers to blockade and potentially transport invasion forces. However, an attacker is generally at a disadvantage; projecting power requires a substantial amount of superiority, since you have long, vulnerable supply lines over the ocean and any kind of amphibious attack, even across a river, means that you risk transporting part of your forces in -- because you don't have transport capability to move all of them at once -- and then having them clobbered while the next batch is coming over. In World War II, Germany unquestionably had much stronger land forces than the UK did, especially after the Battle of France. Mainland Europe was only separated from the UK by about twenty miles of ocean. But that little strip of ocean alone was enough to make an invasion too disadvantageous; Germany considered an invasion, which it had planned as Operation Sea Lion, unworkable unless it could gain both air superiority (which it did failed to do so in the Battle of Britain) and naval superiority (which it was not near either) to keep the Royal Navy and British air forces from turning the invasion into a disaster. And the distance over sea to the US from any major power is a lot larger.

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[–] tal@lemmy.today 3 points 1 day ago (1 children)

[continued from parent]

The US used to be relatively-weaker in a number of areas, but even then, the obstacles were substantial.

If you look at US war plans from the time of World War II, before it became clear that the UK was going to hold out and War Plan Rainbow Five became the guiding plan for the US behind WW2, the US did plan for a scenario where the Third Reich takes over Europe and the Axis comes after the US; the final iteration of this was War Plan Rainbow Four. In that scenario, the goal the US has is to have the US Navy hold off the invasion long enough to complete sufficient mobilization of land forces to make invasion impractical -- that is, the Navy had to buy six months or so -- then to rely on US industrial capacity to build up a naval force to gain ocean control, then push back against them. The US secures all closer landmasses, islands in the Caribbean and such, that might be used as a staging point for a naval invasion; having a closer staging point reduces the transport capacity to move invasion forces into the country in a short period of time.

https://digitalcommons.liberty.edu/cgi/viewcontent.cgi?article=1133&context=masters

Concluded in 1940, Rainbow Four presumed that Great Britain and France had already been defeated by Germany and Italy, while Japan stood ready to strike in the Pacific. It was also assumed that the Axis Powers would acquire the use of one or both of the British and French fleets, thereby giving the Axis naval supremacy in the Atlantic and thus posing a threat to the Western Hemisphere and the Monroe Doctrine. The mission of the U.S. military under Rainbow Four was to defend the Western Hemisphere as defined by U.S. war planners from Greenland to Wake Island against German, Italian, and possibly Japanese aggression. The start date for American mobilization according to planners could be no later than the date of the loss of the British and French fleets to Axis Control. Initially, American and Canadian forces would occupy Newfoundland (which was not yet a part of Canada) and Greenland (which belonged to Denmark), while U.S. forces took control of British, French and Dutch possessions in the Caribbean and South America, similar to versions of War Plan Black and War Plan Red.

U.S. forces would also establish bases in northeastern Brazil, while Argentina, with U.S. support, would assume sovereignty over the British Falkland Islands and also provide for their defense. In the Pacific, U.S. forces would occupy the Gilberts island group as well as Western Samoa, while an expeditionary force prepared to move against any Axis threat posed to South America. Rainbow Four would have required a massive mobilization of U.S. forces because it called for a simultaneous offensive against both Germany and Japan without major allies. Within six months of mobilization the Joint Board had hoped to have at least ten divisions under arms, an unlikely feat even for U.S. capabilities.409 While Rainbow Four gave the U.S. Army an active role in the defense of the Western Hemisphere, unlike the Pacific oriented Rainbow Two and Rainbow Three plans, its defensive approach was out of keeping with national tradition and was anathema to the naval doctrine of keeping potential threats at a distance, for these reasons it was discarded by war planners in mid-1941 along with the other defensive plan, Rainbow One.

An interesting feature of Rainbow Four was the emphasis of war planners on two critical potential dates. The first of these two important dates was the anticipated loss of the British and French fleets to the Axis Powers. The other date was six months after the surrender of the Allied fleets to Germany and Italy. If the British and French Navy’s were simply destroyed, the second date would not matter, but such an outcome was highly unlikely. In the event that both Britain and France were defeated and their navies were surrendered, the date of their surrender would coincide with M-Day (Mobilization Day) in the United States. U.S. war planners hoped that six months after their initial mobilization, that U.S. forces would be ready to implement Rainbow Four if the developing situation called for it. If standing U.S. forces were not ready after six months, they would be supplemented with units from the National Guard.

Note that the concern here was that Germany -- which, in World War II, did not have a substantial surface fleet -- might conquer France and the UK and seize control of their fleets and then use them against the US, to try to make it more practical to conduct an invasion of the US. Note that in the actual war, where France was conquered but the British were not, the British were even more-concerned about this scenario, just with the French fleet alone and themselves as a target. They attacked some of the remaining French fleet after France surrendered, and later Germany attempted to conduct a surprise operation to seize control of the French fleet, which France scuttled while shooting it out with German land forces. When Roosevelt gave a number of US Coast Guard cutters to Churchill early in the war when the UK was desperate for more warships and the US was still ramping up its warship building, he got a personal promise from Churchill that Churchill would see to it that if the UK surrendered, the cutters would be either scuttled or interned at a neutral port, so that they couldn't be turned against the US.

Rainbow Four envisioned a scenario similar to that of Rainbow One. U.S. war planners, however, expanded the field of potential operations to include the entire Western Hemisphere. The special situation of Rainbow Four anticipated the “termination of the war in Europe” which would be “followed by a violation of the letter or spirit of the Monroe Doctrine in South America by Germany and Italy. This was coupled with armed aggression by Japan against United States interests in the Far East. Other nations are neutral.” The purpose of Rainbow Four was simply to “provide for the most effective use of United States Naval and military forces to defeat enemy aggression occurring anywhere in the territory and waters of the American Continents, or in the Eastern Atlantic,” in strength sufficient to threaten U.S. interests and possessions in the Pacific including Unalaska and Midway.

The scenario that war planners envisioned in Rainbow Four was a veritable worst-case scenario for the United States. In the scenario, the U.S. would stand alone against Germany, Italy and Japan. The combined fleet of both Germany and Italy would have been augmented by naval units taken from Great Britain or France making a potential Axis fleet equal to or superior to the entire U.S. Fleet. Under this scenario, Germany and Italy would have declared their intention to take over all British, French, Dutch and Danish colonial possessions and mandates, including those in the Western Hemisphere. Nazi Germany would also have assumed sovereignty over Iceland as Italy assumed sovereignty over the Mediterranean territories of Great Britain and France, and both acquired portions of the West African Coast. Meanwhile, Japan declared the entire Far East to be within her sphere of influence, but it still has significant forces tied down in China. The Soviet Union was neutral, but unfriendly to both the United States and Japan, and at the same time the Soviets hoped to exploit the situation by extending her influence into British India and to foment communist activity in Mexico. In the wake of Great Britain’s defeat, the British Dominions, Ireland and India may have declared their independence from Great Britain. Canada remained technically at war with Germany and takes over Newfoundland from Great Britain. Also, German and Italian immigrants in Latin America agitated against the established governments in the region, whom at this point, with the exception of Mexico, all stood ready to cooperate with the United States in opposing the extension of Axis influence into the Americas. War planners expected that the United States could occupy the various British, Dutch, French and Danish colonies in the Western Hemisphere without encountering native resistance. Strained relations resulting from the new world situation preceded hostilities which may have begun without formal a declaration of war.

The “concept of war” established by U.S. war planners declared that hostilities with the Axis Powers would be followed by a U.S. occupation of all British, French, Dutch and Danish possessions in the Western Hemisphere claimed by Germany and Italy as the spoils of war from the defeated Allies. The war would have initially been an air and naval war as U.S. forces would attempt to cut the Axis Powers communications with the Western Hemisphere. This was seen as a necessary prerequisite for U.S. occupation of British, French, Dutch and Danish possessions in the Western Hemisphere and desired by planners to ensure total political control. The occupation of these and other key strategic areas in Latin America required the use of expeditionary forces to deny the Axis powers use of those territories; therefore, occupational or offensive actions may have been required to insure the total integrity of the Monroe Doctrine, or to defeat any enemy sympathizers within the Western Hemisphere which may have threatened to destabilize friendly overnments. An American alliance with Canada to defend Newfoundland and Greenland and an American alliance with Argentina to defend the Falkland Islands was also sought by the U.S.

This is aimed at keeping any major land invasion forces from having any staging point in the Western Hemisphere, so that the fight is pushed back to extremely long distances over the oceans.

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[–] tal@lemmy.today 2 points 1 day ago* (last edited 1 day ago) (1 children)

[continued from parent]

The security of Panama, the Caribbean, the continental United States, and Alaska including the Aleutians, Hawaii, and Northeastern Brazil were the primary concerns emphasized in Rainbow Four.

The Panama Canal is a strategic weak point for the US, as it controls communication between the major US population centers on the West Coast and East Coast. This was especially true at that point in time, when less overland transport capacity was made use of for domestic transport, and more shipping. A major goal of any adversary would be to sever the US ability to traverse the Panama Canal, so that they could degrade US logistics. If you look at the interwar Fleet Problems conducted by the US, one involved the simulated opposing force managing to sabotage a US battleship traversing the Panama Canal, to sink it in the canal and render it unusable for a significant length of time.

The Caribbean is a potential staging point for foreign forces. Same for Northeastern South America.

Alaska and Hawaii are less-important, though they facilitate control over the Pacific, especially given more-limited ship ranges at the time.

The United States, it was assumed by war planners, would endeavor to adjust disputes with Japan in order to forestall the entrance of that country into the conflict. When the Japanese did enter the conflict, U.S. war planners anticipated that it would probably first seize the Philippines and Guam, as well as launch submarine attacks and surface raids against U.S. communications to Hawaii, Alaska and the Western Coast of Latin America. War planners also anticipated that the financial and industrial resources of the United States would be devoted to increasing at the maximum rate our relative strength particularly in naval, air and mechanized forces. Organized sabotage, industrial strikes and other efforts to hinder this mobilization of resources was expected. War planners also noted that as the U.S. relative strength increased, it would gradually extend American control of the seas into the Western Pacific and the Eastern Atlantic. Rainbow Four plan was also significant in that war planners hinted at United States military operations in Western Africa.

My guess here is that once the US gained sea control, it probably aims to do basically the reverse of what it was concerned about the Axis doing to it -- work up the coast of Africa to invasion staging points into Europe. The fight up the coast of Africa, which has poor logistical infrastructure, favors whoever has naval control, since they can make use of shipping.

The joint mission of the U.S. Military under Rainbow Four was “insuring the security of Continental UNITED STATES, ALASKA, OAHU, PANAMA, THE CARIBBEAN AREA, and NORTHEASTERN BRAZIL, to prevent the violation of the letter or the spirit of the Monroe Doctrine in all the territory of the WESTERN HEMISPHERE” and to “extend military pressure to the WESTERN PACIFIC, the EASTERN ATLANTIC, and WESTERN AFRICA in order to defeat enemy aggression and enable the UNITED STATES to impose terms favorable to itself in the eventual peace settlement.”417 The joint tasks of the U.S. Army and Navy under Rainbow Four were to establish U.S. sovereignty over British, French, Dutch and Danish possessions in the Western Hemisphere. These territories also included Greenland, Newfoundland, Bermuda, the Bahamas, the Leeward Islands, the Windward Islands, Barbados, Trinidad, Tobago, British Guiana, British Honduras, St. Pierre, Miquelon, La Guadeloupe, La Martinique, French Guiana, Curacao, Aruba, and Suriname in the Atlantic, plus the Gilbert, Ellice, and Line Islands as well as Western Samoa, Pitcairn and the Tuamotu Islands in the Pacific.418 Another task of Rainbow Four was to insure the security of the Panama Canal and the Caribbean Area.

Meanwhile, the U.S. Navy was to establish control over the Western Atlantic while the U.S. Army and Marines insured the security of Northeastern Brazil and prevented a violation of the Monroe Doctrine in all the American republics not included in the Caribbean theatre. Over time the United States was to extend American control into the North Atlantic and to defend the North Atlantic Coastal zone, which included Newfoundland, St. Pierre, Miquelon and Greenland. Also, the United States was to control and protect all friendly shipping within this zone and to extend U.S. military pressure into the Eastern Atlantic and Western Africa. The United States was also to defend the Southern Coastal Frontier which included the Bahamas and Bermuda as an outlying U.S. naval base. In the Pacific, the U.S. Navy was to establish American control over the Eastern Pacific and to defend the Pacific Coastal zone, which included the Pacific Coast of the United States and Alaska, including the Kodiak and Unalaska Islands, as well as to control and protect shipping in this zone.425 A key goal in the Pacific was to hold Oahu Island as a main outlying naval base and to protect shipping in the waters around the Hawaiian Islands. A more difficult goal in the Pacific was to hold the entrance to Manila Bay in order to deny it to enemy naval forces, a nearly hopeless task which had long been doubted by war planners.

Manilla Bay was a useful naval base; slowing or preventing capture would delay Japanese advance. In the event, Fort Drum managed to hold out for some months.

But not so as to get lost in the details, the "big picture" goals were to prevent and delay an enemy from being able to conduct a land invasion of the US to buy time for the US to do things like train soldiers and build naval capacity, and to retain US domestic logistical capabilities. The belief that the US would have the ability to delay an invasion force helps mitigate the need to have a large number of soldiers pre-trained.

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[–] tal@lemmy.today 2 points 1 day ago* (last edited 1 day ago)

[continued from parent]

As to the firearms issue, the US has a large number of privately-owned firearms; the next-closest country in per-capita firearms possession has about half the number the US does in per-capita terms. Based on Small Arms Survey numbers, the American public has enough firearms in private arsenals to -- if all of the firearms in all of the arsenals of all of the militaries in the world vanished tomorrow, along with all of the firearms in all of the arsenals in all of the law enforcement agencies in the world, replace them them on a one-for-one basis, then give a firearm to every man, woman, and child in the UK, and then still have millions left over. So in a emergency situation, it's probably likely that the US could get enough armed, albeit untrained, militia on short notice to slow an invasion down -- there's that Red Dawn scenario.

It's important to note that these are not identical to those military firearms. A substantial chunk are handguns, for example, which are considerably inferior to assault rifles...but there are a lot of firearms out there.

There haven't been a whole lot of scenarios where the mainland US has either been invaded or seriously been considered as a target of invasion, so getting solid assessments from foreign militaries as to impact of such a militia is somewhat difficult.

The War of 1812 is maybe the best example, was fought against the British Empire at a time when the US was much weaker, militarily, than the British Empire. In this scenario, a number of battles were fought using militia. In general, the militia performed very poorly when sent on expeditionary forces into what is now Canada; the war was very unpopular, the most-unpopular in US history, and did not want to fight. There are some defensive battles that went poorly for the US, like the Siege of Detroit, where British forces successfully bluffed US defenders into a surrender. On the other hand, there are also some of those that went very well, like the Battle of New Orleans, where a force consisting of a small number of US federal soldiers and a bunch of militia, volunteers and even some pirates fought off a larger attack from British regular forces (albeit that some of those were not infantry).

Germany did have some people spend a while pre-World War I considering invasion of the US, leveraging Germany's superior naval power; establishing German bases in Caribbean countries as a staging point was considered to facilitate this. It wasn't judged to be practical.

In World War I, Germany attempted to get Mexico to invade and annex part of the US, which would distract the US from Europe, drawing forces away and permitting the German military a free hand there. The Mexican government had the Mexican military conduct an evaluation of an invasion and annexation. The Mexican military said that it wasn't practical, in part because of the large number of privately-owned firearms, so at least one military has conducted a formal assessment and considered the private arsenals to be another substantial factor in invasion viability:

Mexican President Venustiano Carranza assigned a military commission to assess the feasibility of the Mexican takeover of their former territories contemplated by Germany.[19] The generals concluded that such a war was unwinnable for the following reasons:

Mexico was in the midst of a civil war, and Carranza's position was far from secure. (Carranza himself was later assassinated in 1920.) Picking a fight with the United States would have prompted the U.S. to support one of his rivals.

The United States was far stronger militarily than Mexico was. Even if Mexico's military forces had been completely united and loyal to a single government, no serious scenario existed under which it could have invaded and won a war against the United States. Indeed, much of Mexico's military hardware of 1917 reflected only modest upgrades since the Mexican-American War 70 years before, which the U.S. had won.

The German government's promises of "generous financial support" were very unreliable. It had already informed Carranza in June 1916 that it could not provide the necessary gold needed to stock a completely independent Mexican national bank.[20] Even if Mexico received financial support, it would still need to purchase arms, ammunition, and other needed war supplies from the ABC nations (Argentina, Brazil, and Chile), which would strain relations with them, as explained below.

Even if by some chance Mexico had the military means to win a conflict against the United States and to reclaim the territories in question, it would have had severe difficulty conquering and pacifying a large English-speaking population which had long enjoyed self-government and was better supplied with arms than were most other civilian populations.[19]

Other foreign relations were at stake. The ABC nations had organized the Niagara Falls peace conference in 1914 to avoid a full-scale war between the United States and Mexico over the United States occupation of Veracruz. Mexico entering a war against the United States would strain relations with those nations.

One can also look at some analogs, like General Henri Guisan in Switzerland aiming to deter the invasion by Nazi Germany -- Operation Tannenbaum -- during World War II via leveraging its armed militia. That wasn't likely exactly the same scenario that the US would face; Switzerland just needed to make Switzerland sufficiently unpalatable and time-consuming to defeat that Germany would not invade when it had other enemies to worry about, not itself to defeat an invasion or slow it sufficiently for other military activities to be performed. But it's an example where it was considered to be relatively-important by a military.

So I think that civilian firearm possession making invasion more difficult is probably a factor, but very much not the primary factor in the eyes of the US military in not needing mandatory military service, if one looks at what US war planning has included -- rather, it's US air and naval strength making any kind of a rapid invasion of the US very difficult, and thus meaning that the US doesn't have the same critical need to have a lot of people pre-trained in infantry tactics.

And there's a cost to that mandatory military service. The time spent in the military is time spent not doing other things -- learning skills in other fields, producing things, etc. You're asking for something like -- depending upon country -- six months of every male's labor. It may be a cost that you want to pay if you don't have a great alternative, but it's not free.

I'd also add, though I do not think that this is the major consideration behind most countries that do do mandatory military service, that having pre-trained infantry can be helpful in an offensive role (or at least defending allies). War Plan Rainbow Five did not expect that the US could conduct major land operations in Europe for an extended period of time; it would need to build training camps and train soldiers. At the outbreak of World War II, the US had a very small army by European standards, smaller than Portugal's. War Plan Rainbow Five leaked to the US press, Nazi Germany did an evalution and concluded that the US could indeed not intervene in Europe with land forces for some months (though they may have already had a pretty good idea just from looking at US capabilities at the time and relying on their own estimates as to training time). So there is some utility outside of just defending oneself. But I think that for the US, as with most countries, the major factor deciding whether mandatory military service is necessary is the need to defend oneself in land warfare on short notice, and as things stand, the US probably won't face a scenario where that is necessary.