It was shortly after midnight on Saturday when bleary-eyed senators, trying to wrap up the 101st Congress, discovered that President Bush had submitted the nomination of veteran diplomat John Bushnell to be ambassador to Costa Rica.

The unusual maneuver prompted speculation that Bushnell was about to be sent to San Jose as a recess appointee -- something Bush could do only if Bushnell's name had been formally submitted to the Senate. Bushnell then would be allowed to serve for one year before Bush would have to renominate him.

But administration sources say no decision has been made on whether to make a recess appointment and avoid Senate confirmation, although they acknowledge one reason for the last-minute move was to keep that option open.

The other key reason for the action, a senior administration official said, was a feeling by Secretary of State James A. Baker III that Bushnell's nomination was being unfairly treated by Sen. Jesse Helms (R-N.C.), the ranking minority member of the Foreign Relations Committee, whose objections had stalled the nomination for months while administration officials attempted to address Helms's concerns.

Helms apparently was not happy with Bushnell's performance as deputy chief of the U.S. Embassy in Panama when the United States invaded last December, Senate aides said. Helms, who sent a detailed memo to the White House with questions about Bushnell's tenure there, also had questions about Bushnell's role in the State Department in 1979 when the Sandinistas came to power in Nicaragua.

"Baker felt he deserved to be nominated," the administration official said. "His life had been on hold for eight months for allegations that have no basis in fact."

Technically, the White House could have nominated Bushnell at any time, but as a practical matter, prospective nominees' names are pre-cleared with key senators. "It doesn't do any good to send a guy up to hang in limbo. Many {at the State Department} said, 'Kill it, it's not worth the fight,' " the official said, but "Baker took a personal interest and said it was not fair. . . . Bushnell had performed very well in Panama."

The administration likely won't try a recess appointment with Bushnell, committee sources said, because that would not only rankle Helms but also other committee members, Democrats and Republicans.

Many members would be upset at such an open attempt to circumvent the Senate and committee liberals are not great supporters of Bushnell, one of the more conservative Democrats in the Carter administration's State Department.

Helms also delayed -- at least until the next Congress -- the nomination of another career diplomat, George Fleming Jones, to be ambassador to Guyana.

Jones was deputy chief of mission in the U.S. Embassy in Chile when Helms visited there in 1986. A Helms aide was accused of leaking U.S. intelligence information to the regime of former president Gen. Augusto Pinochet, who Helms backed, resulting in an investigation of the aide.

Helms has demanded the State Department show him secret cables that he believes will reveal the source of the allegations against his aide. The department has refused to hand over the cables. Helms has blocked Jones, tying up the committee with parliamentary maneuvering.

"If they'd shown him {Helms} the cables," a committee aide said, "they could have moved on Jones." As it is, Jones, who was nominated June 13, also could receive a recess appointment, but more than likely he will be renominated when the new Congress convenes next year.