The AWACS deal with Saudi Arabia, scheduled for a vote in the Senate Oct. 28, tests President Reagan's authority in Congress in his first big foreign policy struggle.
It also tests America's role in the tangled policies of the Near East.
Issues have grown, as the debate progressed, until they seemed to transcend the sale itself.
Some of the questions: Who makes foreign policy, the President or Congress? Is Mr. Reagan's credibility slipping; he is in difficulty on the economic front, how about international affairs? Can a Republican president successfully lobby a majority vote from a Republican Senate?
And abroad there is also the question of Reagan's ability to maneuver in the Near East if he doesn't fulfill his agreement with Saudi Arabia. Will Arabs argue that the United States is unable to carry out commitments to which Israel objects? Former President Nixon publicly noted anti-AWACS lobbying of certain Israeli groups, and Reagan told a news conference that it was ''not the business of other nations to make American foreign policy.''
The House voted overwhelmingly against the $8.5 billion AWACS deal, 301 to 111, with the argument that it introduced disagreement, not harmony, into the Middle East. But the pact takes effect unless the Senate also disapproves it by majority vote. The Senate vote has teetered on the wire with Reagan personally leading an intense lobbying drive for the sale.
It began innocently enough in the Carter administration with negotiation of an agreement to provide so-called F-15 ''enhancements'' (fuel tanks), and a package of other arms. The Reagan administration, on taking office, agreed to these sales and added the AWACS aircraft to the package. The issue is bipartisan. Harold Brown, President Carter's secretary of defense, declared on TV Oct. 4, ''I look favorably on the idea of a transfer of these equipments to the Saudis because I think it would help US security.''
A series of dramatic scenes has followed debate on the Senate floor as hitherto uncommitted members announced their vote. Sen. Patrick Leahy (D) of Vermont declared himself against on Monday, saying ''I take no pleasure in such a vote,'' and urging the President to drop the sale. Senate Democratic leader Alan Cranston of California declared ''the momentum'' was against Reagan.
But the White House says no. It prepared a last minute letter arguing that it has reached accommodations and understandings with the Saudis safeguarding their use. A big argument of opponents has been that the planes might fall into enemy hands revealing American techniques.
The White House argues that opponents of the deal still haven't 51 solid anti-AWACS votes. Reagan is phoning individual senators or inviting them to the White House. After one such visit Monday morning, Sen. William L. Armstrong (R) of Colorado announced his support for the AWACS sale.
Rather than face the loss of prestige of a major defeat some think he might still postpone the issue.
The AWACS debate has broadened since it began. For Reagan it has become a mandate on his ability to conduct foreign policy. The pressure has become so great that some think it transcends the military and political significance. Reagan argued the deal would help stabilize the area against a Soviet threat. He created a furor when he told a press conference that he would not allow Saudi Arabia to become ''another Iran.''
Senate minority leader Robert C. Byrd (D) of West Virginia gave counter arguments:
''Rather than contributing to stability in the region,'' he said last week, ''I fear it will only raise the threshold of tension. . . .