[originally from November 28th, 2014]
That thing about “old enough to die for your country, but not old enough to drink” actually makes sense from the Realpolitik perspective. http://www.ijoa.org/imta96/paper29.html
indicates that: “Over 94% of recent recruits were under 25 years of age, and 82% were 21 or younger”. I see two hypotheses that explain it:
1. People who want to join the military do so as soon as possible. Raising the minimal recruitment age won’t change the overall number of recruits, they’ll just wait another couple of years.
2. Joining the military either requires unhealthily strong patriotic feelings, which are more easy to induce in a teenage brain, or can be a result of severe utility miscalculation and unawareness of opportunities (it’s not like soldiers risking their lives are paid much more than engineers and lawyers), which are also more typical for a teenagers. If they raise the minimal recruitment age, people won’t buy this stuff anymore, and the recruitment rate will drop in a big way.
2.b. Maybe joining the military is not stupid per se, but they still compete with other life choices like college. Thus, it’s important to recruit people before they commit to something else.
If 2 or 2.b are true, the government is basically exploiting the life situation and mental state of teenagers to trick them into dying for their country. Not nice, but efficient as hell.
Drinking, on the other hand, doesn’t provide noticeable benefits for the government, so there’s no incentive to lower the minimal age.