President Carter's decision to ask the Congress for authority and money to revive the military draft system is the first realistic step since 1973 to replace the weakest weapons system in our military arsenal: the all-volunteer force.

The all-volunteer force is an expensive, inequitable and dangerous vestige of the Vietnam War. It is essential to replace it promptly with as fair a draft as we can devise.

Military manpower funds have been buying less and paying more ever since Richard Nixon's commission on an all-volunteer force under-estimated the incremental cost of a volunteer army by several billion dollars. Concerned defense analysts like Sen. Sam Nunn have documented the decline in quality and effectiveness of our armed forces personnel as a result of this misguided experience. To the world, the all-volunteer force has been a nagging reminder that the United States' middle- and upper-middle class lacks the will to fight for its vital interests.

Whether Carter follows his State of the Union rhetoric with vigorous action -- to the point of resuming the draft -- and whether Congress votes him the authority and funds to do so will be meticulously monitored by our allies and adversaries. The issue of revitalizing the draft system is a litmus test of American determination in the face of Soviet aggression and anti-American radical movements in the Third World and Latin America.

Over the next few years, increases in the defense budget (probably larger than the 4.6 percent increase the administration is recommending this year) and American technology can close whatever gap has developed in military hardware between the Russians and Americans. But the whole world is watching to see whether we have the will to use whatever military strength we have. Presidential and congressional action on the draft proposal will provide a good part of the fateful answer.

The move to an all-volunteer force reflected a decision by Americans with money to pay the poorer classes to defend our freedom and fight our wars. "Volunteer" is a fashionable euphemism for "mercenary," however we disguise it in political speeches and attractive advertising to join the "what's-in-it-for-you" Army, Navy, Air Force and Marine Corps. The element of sacrifice was removed from the lives of middle- and upper-middle class youths -- and in large measure taken out of military service -- by increasing the pay significantly to attract the poorer class to enlist. The billions of public-sector dollars needed to do this could better be used to help eliminate the poverty that scars our affluence.

The all-volunteer force offends fundamental principles of American democracy. The draft was never perfect -- John Kennedy's "life-is-unfair" comment was orginally part of a statement defending military conscription. But the draft was an egalitarian means of distributing the often onerous duty of protecting freedom in this treacherous, war-ridden century.

The all-volunteer force makes it too easy for a president and political leaders to embark upon foreign military adventures. We will argue for generations about the lessons of the Vietnam War, but one seems clear: that war did not get sufficient attention from the decisive body politic until Lyndon Johnson was forced to resume the draft to meet Vietnam's voracious appetite for military manpower. At that point, America's middle and educated classes said, "No, we will not sacrifice our sons to this war." That -- not the radical left -- is what put the Vietnam War on the skids.

Carter's decision to resume draft registration wisely puts that issue to Congress and the American people, up front. If the president demonstrates the courage to follow through and Congress and the American people back him, we can provide important evidence of the will to take the necessary action to stop aggression short of war.