It is possible that the creation of an all-professional American army was the most dangerous decision ever taken by Congress. The nation now confronts a political crisis in which the issue has become an undeclared contest between Pentagon power and that of a newly elected president.
Barack Obama has yet to declare his decision on the war in Afghanistan, and there is every reason to think that he will follow military opinion. Yet he is under immense pressure from his Republican opponents to, in effect, renounce his presidential power, and step aside from the fundamental strategic decisions of the nation.
The officer he named to command the war in Afghanistan, Stanley McChrystal, demands a reinforcement of forty thousand soldiers, raising the total US commitment to over 100 thousand troops (or more, in the future). He says that he cannot succeed without them, and even then may be unable to win the war within a decade. Yet the American public is generally in doubt about this war, most of all the president's own liberal electorate.
President Obama almost certainly will do as the the general requests, or something very close to it. He can read the wartime politics in this situation.
The Vietnam war was opposed by the public by the 1970s, when according to the Pentagon Papers, the government itself knew that victory was unlikely. Today the public doubts victory in the war in Afghanistan. However the version of Vietnam history most Americans (who were not there!) read today says there really was no defeat at all.
It is argued that there was only a collapse of civilian support for the war, caused by the liberal press, producing popular disaffection both at home and inside the conscript army, with a breakdown of military discipline, "fraggings" (murders) of aggressive combat leaders, and demoralization in the ranks. This is the version most military officers believe today.
It is an American version of the "stab in the back" myth believed in German military and right-wing political circles after the first world war.
In the US case, the Vietnam defeat was painfully clear at the time, and few believed that either the US Congress or the Nixon Administration (which signed the peace agreement with North Vietnam) were parties to any betrayal of the United States.
Today the revised interpretation of the Vietnam war, claiming that it actually was a lost victory, has become an important issue because most Pentagon leaders are committed to the "Long War" against "Muslim terrorism." An Obama administration order to withdraw from Afghanistan, Iraq (or Pakistan) would be attacked by many in Congress and the media, and by implicitly insubordinate elements in the military community, as "surrender" by an Obama government lacking patriotism and unfit to govern.
Conservative politicians are convinced that any policy not set on total victory for the US in Iraq, Afghanistan, Pakistan - and in coming months, perhaps in Somalia, Yemen, or possibly in Palestine, or sub-Saharan Africa, (or even in an Iran determined to pursue its nuclear ambitions) - would mean American humiliation and defeat.
After Vietnam, Congress ended conscription (which in that war had become heavily corrupt: the poor and working classes were drafted, while many of the privileged had influential families and found complacent doctors or college deans willing to hand over unjustified draft exemptions to those - like the future Vice President Richard Cheney - who had "other priorities" than patriotism and national service.
Congress created a new all-volunteer army. The sociology of the new army was very different from the old citizens' army. The new one was also composed of people who wanted to be soldiers, or wanted the college education that an enlistment could earn you, or often were high-school graduates who didn't have much in the way of other career choices, but since 9/11, and the Iraq invasion, the new army has increasingly relied on immigrants or other young foreigners who can earn permanent US residence by way of a US Army enlistment. The US also increasingly has relied on foreign mercenaries hired by private companies.
Its professional character is fundamentally different from the old army. In the old army, career West Point officers were during wartime largely outnumbered by war-service-only officers, the graduates of Officer Candidate schools or Reserve Officers trained in universities (where much of the cost of higher education could be earned in exchange for a fixed term of duty afterwards as a junior commissioned officer).
Thus the US army from the start of the Second World War to the end of Vietnam was effectively a democratic army, with civilian conscripts, and the majority of its non-commissioned and commissioned officers peacetime civilians, with solid commitments to civilian society, often with families at home - doing their temporary (or "for the war's duration") patriotic duty.
Professional armies have often been considered a threat to their own societies. It was one of Frederick the Great's own officers who described Prussia "as an army with a state, in which it was temporarily quartered, so to speak". The French revolutionary statesman Mirabeau said that "war is Prussia's national industry". Considering the portion of the US national budget that is now consumed by the Pentagon, much the same could be said of the United States.
The new army also has political ambitions. It now dominates US foreign relations with a thousand bases worldwide and regional commanders like imperial proconsuls. Both General McChrystal and his superior, General David H Petraeus, have been mentioned as future presidential candidates. The last general who became American president was Dwight Eisenhower. He is the one who warned Americans against "the military-industrial complex".