ANNAPOLIS, FEB. 25 -- For the second time in two days, leaders of the Maryland General Assembly have rejected a key part of Gov. William Donald Schaefer's legislative agenda, announcing that the governor will get his Baltimore light rail line only as part of a larger statewide rail package -- and with a likely tax increase.

While his lieutenants tried to put a good face on the legislature's action late today, the governor himself was furious. In an off-camera interview with a television reporter tonight, Schaefer declared: "It's war down here now."

The action by the legislature comes on the heels of the Senate's rejection of Schaefer's proposed $20 million math-science high school for gifted students, a move that left the governor fuming. Last week, legislators killed Schaefer's plan to speed up payments to savings and loan depositors, saying it was too risky and expensive. And Schaefer is unhappy with the way the legislature is dissecting the centerpiece of his legislative program: a proposal to revamp the structure for governing higher education.

At the midpoint of the 90-day session, the date Schaefer set as a goal for getting much of his agenda approved or in motion, some are wondering whether Schaefer is in a sophomore slump. After his stunningly successful freshman session, it doesn't appear that the 188-member legislature is likely to be as accommodating this year.

Schaefer has had some victories, including a key committee's approval today of an administration plan to end contested elections for circuit court judges, and aides contend that most of his package is moving along well.

But it is the defeats, both major and minor, that Schaefer has focused on.

Senate President Thomas V. Mike Miller Jr. (D-Prince George's) and House Speaker R. Clayton Mitchell Jr. (D-Kent), along with fiscal leaders of both chambers, termed their light rail decision a "compromise" that ensures all areas of the state are treated fairly and gives the legislature control over the future of costly transit projects. They said they expect light rail projects to require some form of tax increases in the coming years.

While Schaefer sent Lt. Gov. Melvin A. Steinberg out to tell reporters that the administration is pleased with the light rail decision, legislators who have talked to him say he is furious with the idea because it means a delay, at the least, and is accepting it only because he has no alternative.

"The governor's not happy; he said it's down the tubes," said Sen. Michael J. Wagner (D-Anne Arundel), a leading proponent of the light rail project. "I think the governor feels the legislature is really trying to kill it, just like they killed math-science and just like he thinks they're trying to kill the higher education bill."

While legislators say they can't predict the ultimate fate of Schaefer's proposals, they say working with the strong-willed Democratic governor has become no easier with time.

"The lessons we thought we were working with him on didn't stick," said Sen. Laurence Levitan (D-Montgomery), chairman of the Budget and Taxation Committee.

The legislature has not gone out of its way to be adversarial, but it is unwilling to be intimidated by Schaefer's seemingly perpetual bad mood, Levitan said. "We're not going to be court jesters to try to keep a smile on his face."

The decibel level was high at midpoint of the session last year, and many of Schaefer's proposals then appeared to be in deep trouble. But in the end he emerged with more legislative victories than any other governor had racked up in years. An initially reluctant legislature ended up approving his plan for a stadium complex in Baltimore, an increase in the gasoline tax and changes in workers compensation and insurance liability laws, and it allowed his office to keep a good chunk of the so-called income tax windfall that resulted from federal tax revision.

This year looks a little different, mostly because Schaefer already has lost on several valued proposals. While legislators say they are only doing their jobs in passing judgment on Schaefer's iniatives, he is taking the rejections personally.

The governor is placing most of the blame on Miller. While he declined to be interviewed for this story, Schaefer described Miller in today's Baltimore Evening Sun as a legislative bully who is having his committees rough up Schaefer's proposals to show, in the governor's words, that "Miller is a big man."

Schaefer said Miller is trying to kill the administration's omnibus plan for changing the governance of the state's higher education system by carving up the bill and sending it to three committees.

Miller denied that and so far hasn't returned the governor's name-calling. But he appears irritated by Schaefer's words. "It is demeaning to the Senate as an institution and to those senators as individuals," he said.

It is the Senate Budget and Taxation Committee that is set to swing the next punch, as the committee begins deliberations Friday to cut as much as $125 million from the $9.8 billion budget that Schaefer sent to the General Assembly.

Certain to go is a $10 million "contingency fund" that Schaefer asked for and the panel is expected to cut from $5 million to $20 million from an economic development fund that Schaefer holds dear but some lawmakers have criticized as a "slush fund."

But the governor's aides don't think they're doing so badly this year. They point to an early victory on a measure to protect corporate officers and directors from shareholder lawsuits. They are also optimistic about the prospects for a plan to overhaul the way physicians are disciplined and for some of Schaefer's plans to increase the availability of day care.

And despite Schaefer's displeasure, they said they're satisfied with the light rail compromise.

Schaefer has proposed a $290 million rail line from north of Baltimore to Baltimore-Washington International Airport and Glen Burnie.

Under the light rail plan worked out by legislative leaders, only $10 million of the $43 million earmarked could be used this year to begin acquiring right of way and designing the project.

The remaining funds would be held up until next year, for the Department of Transportation to complete a study on light rail around the state and prepare a 10-year financing plan for the state's rail and highway needs. A briefing document legislators prepared for the news media said that the financing plan might "require additional revenues during the 1990s."

At that point, said Del. Timothy F. Maloney (D-Prince George's), chairman of the House Appropriations subcommittee on transportation, "Let's see the big picture and then see if the legislature wants to pay for it."