James Clark Jr., 85th president of the Maryland Senate, was about to bang his gavel to adjourn the Senate Monday night. Suddenly he paused to peer around the old chamber, where his colleagues were shifting in their seats, eager to move from legislation to libations.

The evening had been full of good feeling, with the legislators introducing guests and reading resolutions congratulating people on birthdays and marriages. And, in sharp contrast to the previous week, there had been a minimum of talk and a spate of legislative work completed.

But the warmth in the chamber had an artificial air. These were the same legislators who had traded barbs and openly insulted their leader, Clark, only 72 hours earlier. Mindful of that, Clark decided to make a rare comment before sending everyone into the cool night air.

Gavel in hand, Clark said quietly, "Maybe now that we have reapportionment behind us we can get back to being rational for the next 45 days."

He said it so softly, so quickly that many of the stirring senators had to turn to neighbors and ask, "What did he say?" But the point was clear: Clark recognized that he had been forced into unconditional surrender on reapportionment, but he wanted to make it clear that he wasn't ready to abdicate the presidency.

"I was doing what I had to do, I didn't feel I had any choice in the matter," Clark said after the session Monday night. "Some of the senators said I embarrassed myself by coming off the rostrum. The only thing I was embarrassed about was losing."

According to many, Clark had done what no presiding officer should do: he had given up the rostrum to lead a floor fight--a fight that was very much his own. Clark was doing battle with the Prince George's senators over Gov. Harry Hughes' reapportionment map. Clark was outraged when the governor changed the map, splitting the town of Columbia, which he represents, into two districts and shifting more power to Prince George's. He believed this was a matter on which he could not compromise, and he stood his ground. The result was a crushing defeat Friday, when the Senate voted 29-8 against Clark's motion to cut off a filibuster by the Prince George's senators.

"It's one thing for the president to get involved in the battles," said Rep. Steny Hoyer, now the Democratic congressman from Maryland's 5th District, and Clark's predecessor as Senate president. "I never thought the presiding officer had to be some kind of eunuch on pressing issues.

"But the way he got involved--that surprised me. I don't think I've ever heard of the Senate president leaving the rostrum to go down on the floor to argue an issue. To be at loggerheads with the governor and with the Senate on an issue that is of personal concern--well, that's unusual.

"And getting eight votes. That's got to hurt."

It did. In fact, when Clark had finally withdrawn his amendment to the reapportionment plan and the bill had been voted into law, there was much talk in the Senate that it was the beginning of the end of Clark's presidency, that his removal from the job next January was inevitable.

Reportedly, Hughes views the matter as the climax of four difficult sessions with Clark, and has predicted to politicians that Clark will not be Senate president again.

But those who know Clark are more cautious. They point to his background as an Air Force glider pilot in World War II, to his steady political rise, to the hardball politics he played in 1979 to get the presidency.

"Jim Clark finds a way to survive," one legislator said. "People are deceived by his looks and his drawl. Underneath all that, he's a tough fighter."

Clark appears to be the laid-back country politician, with his shock of white hair and bushy white eyebrows. He speaks slowly, his gravel voice rarely rising, and tends to cut through the political rhetoric to make his point.

"What do I think will happen as a result of all this?" Clark said, swiveling in an office chair. "I think the Senate of Maryland will go on with its business.

"I know a lot of harsh things have been said about me; I wish they had gone unsaid. But the way I look at it, the people who say things like that are harmed more by them than the person they say them about.

"The people of my district have been unrepresented down here for 30 years. I represent 160,000 people. Each of the Prince George's senators represents 80,000. At last my people had a chance to be represented and the governor changed that around. I did what I had to do; so did the governor; so did the Prince George's senators. If they were in my shoes, they would have done the exact same thing. Every one of them."

In splitting Columbia, Hughes contended he in fact was giving the boom town more clout, since it is expected to grow enough to dominate both the districts it will straddle. Clark remains unconvinced.

"Anyway," he said philosophically, "the General Assembly shouldn't be allowed to deal with reapportionment. That's been the problem."

The problem now, for Clark, is getting the Senate back on track, back to dealing with the key issues still left on the agenda: the gas tax, the drinking age, gun control, auto emissions inspections and interest rate ceilings.

"The Senate will be just fine," said Sen. Harry McGuirk (D-Baltimore) who has witnessed the floor battles for 16 years. "The leadership will do what it has to do and the work will be completed."

Clark agrees. He pointed out that Monday night's session put the Senate back on schedule. But political memories tend to be long ones and Clark, who has been here for 24 years, knows his reapportionment defeat may have been just a warm-up for a bigger fight--for the presidency--next year.

"I don't even know if I'll be here next year," he said, smiling, when the subject came up. "I've always been a believer in crossing my bridges when I come to them."