When the Senate Armed Services Committee voted 11-9 along party lines this week to reject John Tower's nomination as defense secretary, it did more than just hand President Bush the first major defeat of his administration.

It also set the stage for a partisan fight in the full Senate, where the Democrats hold a 55-45 majority. And it raised the strong possibility that Tower could become only the ninth Cabinet nominee ever rejected for confirmation.Even as it is now, the long fight over Tower's nomination has undermined Bush's efforts to improve relations between the White House and Congress, impaired his plan to improve the tone of government ethics, and put many important decisions at the Pentagon on hold.

Under these extraordinary circumstances, it's easy to understand why there are many calls for Bush to withdraw the nomination or for Tower to step aside.

But Bush cannot abandon Tower without impugning his own judgment in making this nomination and in effect telling nominees for other posts yet to be filled in the new administration that they risk abandonment, too.

The Senate critics of Tower, however, are also putting themselves on the spot. In effect, they are saying: Never mind that George Bush served his country as a combat veteran in World War II, as director of the Central Intelligence Agency, and for eight years stood a heartbeat away from the Oval Office. Never mind, either, that Bush now serves as commander in chief of all this nation's armed forces.

Despite those qualifications of President Bush, the critics have put themselves in the position of insisting that they know more than he does about who is best qualified to serve as secretary of defense.

That's not to minimize the seriousness of the accusations against Tower. Perhaps the most damaging words against Tower were uttered by Chairman Sam Nunn of the Senate Armed Services Committee when he said:

"I cannot in good conscience vote to put an individual at the top of the chain of command when his history of excessive drinking is such that he would not be selected to command a missile wing, a SAC bomber squadron, or a Trident submarine."

This concern, however, could easily be put to rest. We like the recent suggestion from the Baltimore Evening Sun that Tower unequivocally state that he will give up the use of alcohol while he is secretary of defense. This would be a simple step if Tower is not an alcoholic and an essential step if he has a drinking problem.

Meanwhile, the public is being treated to a prolonged rehash of the familiar and basically unsubstantiated accusations against Tower. Now that its Armed Services Committee has acted, the full Senate should move quickly to vote on Tower so that, one way or another, the Pentagon can get on with its unfinished business.