ALBANY — With the help of Assembly Democrats, Governor Spitzer is tightening the screws on the Republican Senate majority leader, Joseph Bruno, whose increasingly lonely position in budget negotiations could force him to succumb to the governor’s demands on health care, education, and taxes.

At a feisty negotiation session in the executive chamber, Mr. Spitzer and the Assembly speaker, Sheldon Silver, ganged up on the 77-year-old silver-haired Senate leader, who is battling to restore the entirety of the governor’s proposed Medicaid cuts, pour more money into Long Island school districts, and substitute in a property tax relief plan that does not exclude wealthier homeowners.

Mr. Bruno came under attack from multiple directions: Messrs. Spitzer and Silver; the Republican Assembly minority leader, James Tedisco; the Democratic Senate minority leader, Malcolm Smith, and the Democratic lieutenant governor, David Paterson, each criticized Mr. Bruno for proposing a budget they said was unrealistically high.

“What I’m saying to you, Joe, is that it’s time to make those tough decisions,” Mr. Spitzer said.

He accused Mr. Bruno of playing a game of “three-card monte” with budget numbers.

“Every time you look underneath to find the money, it’s not there,” the governor said, sitting at a hulking wooden table covered in casino-like green felt.

Mr. Bruno said he didn’t mind the piling on. “I think it’s even,” he said. “Five of them and one of me.”

Maintaining calm, Mr. Bruno refused to budge and insisted his spending plan was affordable, arguing that Albany annually underestimates its available revenues. Spitzer administration officials calculated Mr. Bruno’s spending plan at just under $124 billion, more than $3 billion more than the Senate’s estimate, which does not include money spent on giving rebates to homeowners.

The governor proposed a budget of $120.6 billion, and the Assembly came out with a plan totaling $121.2 billion.

Mr. Bruno defended the Senate’s efforts to eliminate the governor’s proposed $1 billion in cuts to hospitals and nursing homes, saying that slashing Medicaid funds doesn’t “represent reform.”

He said Mr. Spitzer’s plan to slightly increase New York City’s share of public school funding would unfairly punish Long Island schools, which are receiving more money but a smaller slice of the pie.

He argued that much of his proposed new spending helped businesses and residents by lowering taxes for more people and blocking Mr. Spitzer’s plans to close a variety of tax loopholes. “If you want to count that as spending … then we’re big spenders,” Mr. Bruno said.

At times, the leaders addressed Mr. Bruno with a tone of concern that one would use to speak to a troubled friend in need. Mr. Smith told Mr. Bruno that if needed help crunching budget numbers, he would lend him members of his staff. Mr. Bruno refused the offer.

The summit took place in the Red Room of the executive chamber, an ornate space of stained glass, mahogany wainscoting panels, bronze leaf decorations, and coffered ceilings. The stately setting belied the aggression of the participants.

Near the beginning, Mr. Bruno complained that there was no water at the table. Mr. Spitzer responded: “You’re just beginning to learn my negotiating tactics — there’s no water. And there’s no bathroom.” He may have been joking, but Mr. Bruno looked like he really needed the water, which he later received.

In the Pataki era, Mr. Bruno was ensconced in the role of middleman and no-nonsense dealmaker, playing off the vulnerabilities of the governor and the intransigence of Mr. Silver. With a Democratic governor in power, Mr. Bruno has had to assume the role that Mr. Silver played so well, the odd man out.

While Mr. Silver famously used a stubborn stance to wrench concessions from Governor Pataki, Mr. Bruno is finding it difficult to exploit the same tactic of delay. One problem for the majority leader is that Mr. Silver — eager to mend his relationship with Mr. Spitzer after defying him during the comptroller search — has decided to abandon Mr. Bruno and ally himself with the governor.

“Last year we partnered,” Mr. Bruno told Mr. Silver. “The year before we partnered. Where are you now? What’s happened?”

Albany lawmakers said yesterday it was possible that Mr. Spitzer and Mr. Silver could pass a two-way budget, putting even more pressure on Mr. Bruno to compromise.

Mr. Bruno also must watch out for Mr. Spitzer gaining an advantage by picking off votes from his conference, which holds a slim two-seat majority in the Senate. Mr. Spitzer suggested yesterday that he was in talks with other Republican senators.

Also, a late budget could hurt Mr. Bruno more than Mr. Spitzer, whose popularity among voters and his support from other lawmakers would make it easier for him to pin the blame for delays on the veteran Senate leader.

Mr. Spitzer, who has said he would not hesitate to prolong negotiations into April and beyond if he doesn’t get the concessions he wants, would likely use a breakdown in talks to batter Mr. Bruno, giving his conference bad publicity at a time when its trying to preserve control.

Albany has just started getting accustomed to passing its budgets on time after annually missing the April 1 deadline between 1985 and 2004, a streak of gridlock that had come to symbolize Albany’s disarray.

“The issue of an on-time budget is not going to be a significant factor in what happens here,” a top adviser to Mr. Spitzer, Lloyd Constantine, told The New York Sun. “If you’ve got a threat, and they say make my day, then the threat has been substantially taken away.”

Lawmakers outside Mr. Bruno’s conference described the Republican Senate’s position as a lose-lose situation: “He’s either seen as a big caver or seen as doing business as usual,” a Democratic state senator and former minority leader, Martin Connor, said.