Maryland Gov. Robert L. Ehrlich Jr. yesterday launched a fresh campaign to win Senate confirmation for his embattled nominee to head the Department of the Environment after rejecting a compromise with environmental activists who oppose the nomination.

Without a deal, the stage is set for a showdown today between the new Republican governor and liberal Democrats fighting to block the appointment of Lynn Buhl. The Maryland Senate has never before rejected a Cabinet nominee, and the feud over Buhl has emerged as the first major test of Ehrlich's skill in working with the Democrats who control both houses of the General Assembly.

Late yesterday, both sides were predicting that they would prevail when the Senate is called to vote on Buhl, a former auto industry attorney and environmental regulator from Michigan who has been criticized by environmentalists as being unqualified and too lenient toward big polluters. Buhl was rejected 10 to 9 last week by the Senate committee that vets gubernatorial appointments.

Sen. Brian E. Frosh (D-Montgomery), who is leading the opposition to the nomination, said he was "confident she will not be confirmed."

Ehrlich's communications director, Paul E. Schurick, said the governor had "promised to go to any and all lengths to save the nomination. And we are."

With 10 Republicans in the 47-member Senate, Ehrlich needs at least 14 Democrats to win. Ehrlich has said he can assemble the votes if Senate President Thomas V. Mike Miller Jr. (D-Prince George's) gives him "a level playing field." Yesterday, Schurick said Miller again assured Ehrlich that he is not actively working against the nomination and that he would "let this confirmation go on its merits."

Though Miller voted against Buhl in committee and urged Ehrlich to withdraw her nomination, he began trying to broker a compromise between the governor and environmentalists after Ehrlich made it clear that he would not back down. The battle over Buhl has put Miller in the awkward position of embarrassing Ehrlich, a key ally on slot machine gambling, or defying a key Democratic constituency.

On Friday, Miller arranged a meeting between Ehrlich and Frosh, one of the General Assembly's most respected voices on behalf of environmental protection. At the time, Ehrlich offered to cut a deal, telling Frosh he would consider any change in personnel or environmental policy if Frosh would withdraw his opposition.

On Saturday, Frosh proposed a compromise: Pull Buhl's name off the Senate floor, allowing her to serve for a year on a kind of probation. Ehrlich could then resubmit her name for confirmation when the Senate convenes in January.

Frosh also asked Ehrlich to replace Kendl P. Philbrick, a former vice president at Lockheed Martin Corp. now serving as deputy secretary. Environmentalists have been even more critical of Philbrick, accusing him of being too close to business interests.

Frosh also sought a variety of concessions on environmental policy and personnel, including giving environmentalists a formal role in helping to fill posts on the Critical Areas Commission, which has veto power over construction projects within 1,000 feet of the Chesapeake Bay and its tributaries.

Ehrlich rejected Frosh's proposals, said Schurick, who called a probationary period for Buhl "the worst possible outcome."

Frosh is "asking for things that aren't possible," Schurick said.

Late yesterday, Miller said he doubted that a deal could be reached before the vote this morning. "The problem is, the governor's got these good angels and bad angels advising him," Miller said. "I think the right-wing angels are holding sway on this one."

After rejecting Frosh's proposals, Ehrlich renewed his lobbying efforts. Throughout yesterday, Ehrlich and top aides contacted Democratic senators, arguing that defeating Buhl is not worth the damage it would do to relations with the governor, who holds veto power over their bills, appointment power over their local boards and commissions, and budget power over their local projects.

Ehrlich's team also told senators that he would not name a new environmental secretary if Buhl goes down, leaving Philbrick to run the department. "I think that message is getting delivered loudly and clearly today," Schurick said.

At the same time, Frosh and other environmental activists were lobbying hard to hold onto the slim majority they claimed last week. And they enlisted the help of Montgomery County Executive Douglas M. Duncan (D), who confirmed that he placed calls to two Montgomery County Democrats, Rona Kramer and P.J. Hogan, who so far have not committed to voting against Buhl.

"At last count, we had the votes," Frosh said. "I guess we'll see tomorrow whether that's changed."

Lynn Buhl talks with University of Maryland Board of Regents member Richard Hug before recent confirmation hearings in Annapolis.