Elliot J. Feldman, a Washington lawyer, was a special project officer and consultant in the Defense Department during the Reagan administration.

Those suggesting that the United States return to military conscription — including Thomas E. Ricks, writing recently in The Post, and my former boss at the Pentagon, Lawrence Korb — surely have honorable intentions. But they should know better. They cast a historical eye toward Vietnam and Korea, but they seem to have forgotten why we resorted to an all-volunteer armed force. The reasons applicable in 1972 are even more compelling today.

Among the reasons Ricks, Korb and others have cited for the change they propose is the extent to which our armed forces have been broken by the wars in Afghanistan and Iraq, producing tragedy in those countries and within our military. They also note the detachment from civil society that our troops experienced during these wars. The concluding argument is always the same: Had the troops been conscripted, we would have ended these wars more quickly because the American people would have objected sooner to the futility of the missions. Without such democratic pressure, they assume (and without reference to the decisions of the Obama administration), national leaders will not easily withdraw.

These observations are seriously flawed. There may be no historical precedent for the professionalism and success, within their missions, of the all-volunteer U.S. forces since their creation. The most important problems have arisen from policies of stop-loss (effectively an unofficial selective draft) and the abuse of reservists, who did not expect to spend prolonged periods in combat. These problems are partly attributable to the size and scale of the armed forces, which were dictated by the economics of a volunteer force.

Such criticism assumes that with a draft we could have maintained a much larger force, but that is not the case. The economics of training and equipping a much larger military would have been as challenging, compounded by the famous problems of morale and efficiency with conscripted soldiers — lessons we supposedly learned in Vietnam. The truth is that missions must correspond to capabilities, not that we can redesign capabilities for ever-expanding missions.

Another flawed rationale in calls to restore the draft is that Americans would be more mindful of misbegotten wars. Here the amnesia about Vietnam is distressing. Americans supported that war by significant polling margins for more than five years, until nearly 550,000 troops were on the ground in the combat theater, a number exceeding the maximum commitments in Iraq and Afghanistan by multiples of more than three and five, respectively. The draft created an illusion that we had unlimited potential manpower. It seduced our leaders into spiraling escalation, with body counts of communists and imagined light-at-the-end-of-tunnels offered as justifications. It took a protest culture of the 1960s to press for an end to the war.

There is also a distressing amnesia about why we jettisoned the draft. The most important reason, with echoes in the impressment of the War of 1812, the lottery and purchased substitutions of the Civil War, and the Selective Service of World War I, is demographics. The United States has too many people to have a draft. We have no rational way to decide who should don a uniform and who should get on with their civilian lives. The certainty is that we cannot take every eligible, qualified person of age. We would never need forces that big and could not afford to train, house and maintain them. Nor could we afford alternative service for everyone or decide who would get to do alternative service and who would have to be a soldier. Such programs failed when we tried them, largely because they were fundamentally unfair. Other countries, notably France, the founder and most faithful devotee of conscription, have given up on them for the same reasons.

The answer does not lie in larger forces that we cannot afford nor in a coercive system that is inherently unfair. The U.S. military must rely on volunteers, but we must also be fair and generous with them. They need reasonable compensation and the prospect of fulfilling professional careers, recognizing the complexity and sophistication of modern warfare. They must be treated with gratitude and respect, with premier health care and a future should they elect to return to civilian life. All of that is expensive, but not nearly as expensive, we seem to have forgotten, as a draft.

Further, we must understand what we are capable of and stop posturing that, with force, we can do anything. There is nothing patriotic about sending young people to wars that cannot be won or to transform foreign countries uninterested in our way of life. It is not so much about being modest as it is about being realistic. We should recognize what we can do and maintain the capability to do it. No less, but no more.