SACRAMENTO — The issue was whether the UC Board of Regents would approve a 24% fee increase for the next academic year, and Lt. Gov. Leo T. McCarthy found himself on the losing end of a 20-to-1 vote.

With most of the regents convinced the fee hike was necessary because of budget problems, the issue was never really in doubt. But it posed a more personal question for McCarthy. Could McCarthy, at 61 and campaigning for the U.S. Senate, his fifth statewide race in the last 10 years, still get excited at such things?

"You bet," McCarthy snapped at an interviewer who raised the question. "Underneath, the fires still burn."

Frequently described as controlled and bland, despite a political career of almost uninterrupted conflict, McCarthy got highly emotional just thinking about the regents' vote last month. His bright blue eyes and gravelly deep voice alternated between anger and compassion as he talked first about the regents and then the students.

McCarthy called the regents "detached," and said they considered problems of the students "abstractions."

"Read those," he said, pointing at about 400 letters neatly stacked in four bundles on his desk. The handwritten letters contained pleas by students and McCarthy hears a touching, human voice behind each one.

The veteran Democrat said that each time he gets embroiled in a fight on behalf of a relatively powerless group he feels a sense of renewal, a rediscovery of the intense Irish-Catholic kid who grew up in San Francisco's Mission District with an appetite for political combat that enabled him to jump from a seat on the local Board of Supervisors to Speaker of the state Assembly in just over six years.

"I've never backed off a good fight," said the veteran officeholder, who is in the thick of another one as he campaigns for the Senate seat held by incumbent Sen. Alan Cranston, a fellow Democrat who is retiring.

McCarthy finds himself at the top of early public opinion polls, leading his two primary opponents--Rep. Barbara Boxer, from Marin County, and Rep. Mel Levine, who represents parts of West Los Angeles and beach communities in Congress.

But both Boxer and Levine, helped by their positions in Congress, have been raising more money than McCarthy, and no one is predicting an easy race.

As the lopsided vote on the student fees indicates, McCarthy is a long way from being the political presence he was as Assembly Speaker during the 1970s when he made his political reputation.