WASHINGTON -- President Clinton, standing beside police officers and the loved ones of three murder victims, made an impassioned appeal yesterday for Congress to reverse its vote of last week and pass a $33 billion crime bill.

"If Washington had acted six years ago, some of these lives might have been saved," Mr. Clinton said, referring to the long-stalled crime legislation. "If Washington will act this week, a whole lot of lives can still be saved."

The bill contains money toward hiring 100,000 new police officers and building new prisons. It expands the death penalty, makes "three strikes and you're out" the law of the land for federal crimes and bans most assault-style weapons. It also contains billions of dollars for programs aimed at preventing crime -- drug treatment, self-esteem courses, and anti-rape and anti-abuse educational efforts.

Until recently, the bill enjoyed bipartisan support. But faced with a blitzkrieg of attacks from the National Rifle Association and the determined opposition of the Republican leadership in the House, which maintains that the bill has grown to include too many costly social programs, it was blocked from consideration last Thursday by a vote of 225 to 210. Fifty-eight Democrats voted with the Republican opposition.

An angry Mr. Clinton immediately took to the presidential bully pulpit. On Friday, he flew to Minneapolis, where he spoke contemptuously of the Republicans and the NRA at a police convention. And Sunday, he made a passionate appeal for the bill at the Full Gospel A.M.E. Zion Church in Prince George's County.

The goal was to pressure members of Congress who had voted against the bill -- and to let them know that the president intends to keep the pressure on.

"The members are starting to feel the heat," said White House communications director Mark Gearan.

Mr. Gearan said that the White House strategy is to seek minor changes in the bill this week and then bring it back for a vote tomorrow or Thursday -- a vote that White House officials believe could define the Clinton presidency.

The House vote to block the bill from consideration clearly embarrassed Mr. Clinton. And even Democratic loyalists on Capitol Hill fear that failure to quickly pass a crime bill would pose a threat to his health reform legislation.

The president played down such talk about his personal future yesterday, tacitly acknowledging that it might be counterproductive because it would give Republicans an incentive to oppose the bill. Mr. Clinton insisted that ordinary Americans couldn't care less who gets credit for the bill -- they just want Washington to wake up to America's demand that the government do something about violent crime.

To dramatize this view, Mr. Clinton arranged for himself to be upstaged by Marc Klaas, Steven Sposato and Janice Payne -- each of whom had suffered an extraordinary loss.

"It's too late for Polly," Mr. Klaas said of his 12-year-old daughter, who was kidnapped out of her bed at night and murdered on a rainy night on California's north coast. "It's not too late for your daughter."

Mr. Sposato's wife, Jody, was killed in a San Francisco law office last July by a deranged killer armed with two assault-style pistols -- weapons he might have difficulty buying under the new law. She left behind a 10-month-old daughter, Meghan, who is starting to talk, her father said.

"Daddy, I want to see mommy," she says.

"A murder like this could have been prevented," said Mr. Sposato, who added that he has been a Republican for 19 years and is deeply disappointed in his party. "It's not the crime bill that's being held hostage -- it's the American people."

The third parent was Janice Payne of New Orleans.

"On April 29, as a class project, my son James wrote a letter to the president asking him to stop the killing in the city," she told the hushed Rose Garden crowd. "He said: 'I think that somebody might kill me. I'm asking you nicely to stop it. So please do it. I know you could.'

"Then, nine days later, my son's life was taken away," she added. "It was May 8th -- Mother's Day."

James Darby was 12 years old when he was shot to death while he walked with his family.

When it came time for the president to speak, he said that he had read James Darby's letter "over and over and over again."

"He said, 'I know you could do something about this, and I'm asking you nicely to do it,' " Mr. Clinton said. "Well, my fellow Americans, we have asked the Congress nicely long enough. There should be no more excuses, no more tricks, no more delays, and no more discussion about whether this bill is a Democratic bill or a Republican bill or a Clinton bill. . . . So let Congress hear this: Pass the Darby-Klaas-Sposato crime bill -- and do it now!"

Only 11 House Republicans supported the bill last week, and the president's initial reaction was to blister the Republicans. Yesterday, he sounded less partisan. Partly, aides said, this was because as they try to identify eight House members who might switch their votes this week, White House strategists realize that some of them are likely to be Republicans.

Treasury Secretary Lloyd M. Bentsen, in an interview yesterday in his office, revealed that Cabinet members and other key officials and allies are working from lists of prospective vote-switchers.

At the top of the list are the 17 Republicans who voted for the crime bill in April and who also voted for the assault-weapons ban in a separate vote -- but then turned around and voted against the package last Thursday. They include Rep. Wayne T. Gilchrest, who represents Annapolis and the Eastern Shore.

"I think they have some explaining to do," Mr. Bentsen said. "So do the 58 Democrats [who voted against the bill]. Obviously, it's an all-out effort to turn around eight votes. But it won't be easy."

Bruce Reed, a White House domestic policy adviser, agreed but sounded cautiously optimistic. "It's only eight votes [that need to be switched]," he said. "That's not many, is it?"

Mr. Bentsen has also held some private "prayer meetings" with Democratic members of the Texas delegation who voted against the crime bill -- votes due almost entirely to the inclusion in the bill of the weapons ban. In those arm-twisting sessions, Mr. Bentsen emphasizes that he, too, hails from a rural Texas county where guns are far more popular than federal regulations.

"But I think they've made a miscalculation," he said. Referring to the "Street Sweeper," one of the more notorious assault weapons targeted in the bill, he added, "I can't imagine someone using that in a duck blind."