Conscription, once prevalent among major military powers, has become a subject of some controversy in recent years. The United Nations Universal Declaration of Human Rights implicitly condemns it. Human rights advocates often state that compulsory martial service is a form of institutionalized slavery. Some military theorists maintain that conscription is simply not a viable long-term strategy, as an all-volunteer force is implicitly superior in skills and morale.

Nations that practice conscription cannot be easily categorized along geographic or ideological lines; most see it as an essential fact of self-defense-a regrettable necessity, but a necessity nonetheless. Though relatively few nations forcibly enlist all men of military age, half the countries of the world still demand compulsory military service of at least some citizens; most of the remainder reserve the right to levy additional troops in wartime.

None of the major English-speaking military powers currently conscript its citizens; the United States was the last to discontinue the practice in 1973. However, upon turning 18 all US males must register for “the draft” (under the euphemism “Selective Service”) and the US Congress periodically considers legislation to reinstate the draft.