When Sen. Patrick J. Leahy (D-Vt.) offered a proposal in the Appropriations Committee yesterday to cancel development of the B-2 bomber, he was confident he had at least a one-vote majority of the 29 members, according to a spokesman.

What he did not know was that the proxy he had from Sen. Harry Reid (D-Nev.) to kill the plane was worthless. "One of my relatively new legislative people, without checking with me, fixed my mechanical signature to {the proxy} and sent it to over {to Leahy's staff}," said Reid. He said he supports Leahy's proposal but didn't want to "kill the program in the committee," preferring instead to wait for a vote on the Senate floor.

When the committee met yesterday to complete work on a $268 billion defense bill for fiscal 1991, it voted 15 to 14 to table the Leahy proposal. The action left intact a $4.3 billion appropriation for the B-2 that would lead to purchase of two B-2 squadrons. House-Senate conferees on the 1991 defense authorization bill are seeking to reconcile sharp differences over the B-2.

Leahy's proposal -- which was defeated 56 to 43 on the Senate floor in August -- would end procurement at only six planes and allow funding to continue only for research and testing.

"I work closely with Danny Inouye," Reid said, referring to the Hawaii senator who is chairman of the defense appropriations subcommittee. "I thought it was the right thing to do. He knows I will vote against it {the B-2} on the floor."