On Senate floor-a somber occasion

They quoted Gide and Solzhenitsyn, DeGaulle and Lincoln. There were truly anguished speeches, but a marked lack of the posturing and speechifying usually expected of the US Senate. In the end, one was struck by how human were these 100 men and women who had just voted to approve the largest arms sale in the nation's history.

As he sat in a chair, surrounded by reporters and photographers in the Senate press room explaining his vote to send the AWACS and other sophisticated weaponry to Saudi Arabia, Sen. William Cohen (R) of Maine seemed small despite his tall good looks and expensive senatorial garb. There was a troubled look about his eyes.

Out in the hallway, Sen. Larry Pressler (R) of South Dakota, who also had voted to support the President, looked equally troubled as he moved through the crowd. His was not the demeanor of one on the winning side of an historic Senate vote.

It has been declared a great victory for the President, but there is a sense among many that this remains to be seen. Of all members of Congress in the House and Senate who voted on the AWACS question, less than one-third sided with the administration. And of those who did, a great many did so with considerable reluctance.

Like ''supply side'' economics, this important diplomatic question is based on trust in an untested theory. Will Saudi Arabia - a country that supplies the PLO and currently harbors Idi Amin - now be more forthcoming in that region's quest for peace?

This question pervaded the heart-felt speeches of men like Senator Cohen, who earlier had sided with the anti-AWACS forces.

''I fault the administration for making this a major diplomatic test,'' Cohen said softly to a packed and hushed Senate gallery. ''I don't share the administration's confidence that Saudi Arabia will be more moderate in the future than they have been in the past.''

But in the end, he said, with much talk of growing anti-Semitism in this country, he had ''come to the conclusion that if this sale is rejected, Israel's security will be lessened.''

Bob Packwood, Oregon's maverick Republican senator, paced behind the Senate chamber desks. He had led the fight against AWACS and seen his seemingly solid majority slip away under White House pressure. He smiled and talked pleasantly with aides and visitors, but when he turned away, the slope of his shoulders told that he knew he had lost several hours before the close vote.

''Peace is not going to come by further arming the Middle East,'' he argued when it came time to speak. ''Saudi Arabia already has the sixth largest arms budget in the world and far and away the highest per capita arms budget. Not one other country on the Arabian peninsula has publicly endorsed this sale and it's understandable. They dislike and distrust, with justification, Saudi Arabia's motives.''

Offstage in an anteroom, a Saudi prince sat smiling as the clerk called the role. Sensing the history of the moment, members of the House of Representatives drifted into the back of the senate floor. Robert McClory, who's been on Capitol Hill for 20 years. John LeBoutillier, a young first-term congressman not long out of Harvard.

Outside in the Washington dusk, a crowd gathered to watch for famous faces. TV lights gave it an opening-night atmosphere. As he waited to be interviewed by a young reporter, Sen. Jake Garn said to no one in particular: ''This has been the most blown-out-of-proportion issue in the history of the Senate.''