Vice President Bush tonight accused New York Gov. Mario M. Cuomo, a potential rival in the 1988 presidential campaign, of being soft on crime and took him to task for "telling us to be ashamed to stand up and say we're proud of this great land."

In a speech before the New York State Conservative Party, Bush said one example of "the difference between a liberal politician and a conservative one [is that then-California] Gov. Reagan kept cop-killers in jail."

The reference was to a recent grant of clemency by Cuomo to Gary McGivern, convicted of felony murder in the killing of a deputy sheriff in New York. The clemency grant, which prompted an outcry from many New Yorkers, made McGivern eligible for parole, but the New York Parole Board has since voted not to grant it.

Bush's appearance here on the same stage with Rep. Jack Kemp (R-N.Y.) was expected to spark some intraparty fireworks in the ongoing "fight for the right" among GOP presidential hopefuls, but the vice president chose instead to aim his broadsides at Cuomo, a Democrat.

Last week, Cuomo publicly vented anger at "ethnic slurs" that he said have cropped up in recent newspaper columns disparaging the idea that an Italian can be elected president. Tonight, Bush interpreted Cuomo as follows: "He's telling us that new Democrats advocate the same old destructive politics of divisiveness and resentment . . . ."

"Worst of all, he's telling us to be ashamed to stand up and say we're proud of this great land and the freedom and opportunity it has made possible for generation after generation."

The interpretation was confusing. Bush appeared to be taking the same position Cuomo has articulated -- that ethnicity should not be a factor in political viability -- but he couched his remarks as a criticism of the governor.

"His [Cuomo's] people tell us we're supposed to feel sorry for Gov. Cuomo because he has got such a tough life," the vice president said.

Cuomo responded to Bush's speech in a statement, recommending the vice president should "read my comments regarding ethnicity and the political process. He would learn that we are in complete agreement that ethnicity should be irrelevant."

Bush's news secretary, Marlin Fitzwater, said it was the vice president's idea to carry the attack against Cuomo, who has incurred the wrath of the White House by leading the campaign against the repeal of state and local tax deductibility, a key feature of the Reagan administration's tax-reform proposal.

"He saw an opportunity to dramatize the difference between Republicans and Democrats instead of focusing on intraparty differences," said Fitzwater.

Kemp, who spoke to the audience of 1,000 after Bush, also sought to play down the intraparty rivalry, noting just before the ceremony, "I'm not here to pick a fight with the vice president . . . . There's plenty of time if it comes to that."

Nevertheless, there was considerable jockeying just to get the two on the same stage. Kemp, who has been endorsed by the small but symbolically important fringe party in all his campaigns for Congress, originally turned down the invitation to speak because of a schedule conflict. When he learned Bush was speaking, however, he made room for the event.

Bush strategists say they believe the only way the vice president can be challenged in the 1988 nomination battle is from the right, and they have made it their top priority in recent months to show that Kemp does not have a lock on the conservative wing of the party.

Bush played to the crowd tonight by pledging to reject all "whispers" to the effect that he should find a way to distance himself from the president: "Let me tell you something. Even if it costs me my political career, I'm not going to distance myself from the president. I don't pick the issues on which I stand with him and the issues on which I don't. We came in this thing fighting for the same principles. We've fought side by side every step of the way. Maybe it's the old Navy pilot in me, but I believe you don't cut and run on your friends."

Bush will continue his appeal for the conservative vote with a speech Friday to the Rev. Jerry Falwell's Liberty Federation [formerly the Moral Majority], and next week to another conservative group.

Kemp sought to upstage Bush by arranging for a near-endorsement, just before the dinner, from Lewis Lehrman, the 1982 GOP candidate for governor in New York who is now chairman of Citizens for America, a citizens' action group aimed at advancing the Reagan agenda. Lehrman introduced Kemp glowingly at a rally for activists, and said he would make a formal endorsement "as soon as Jack becomes a formal candidate."

Kemp called support for freedom fighters in Afghanistan, Cambodia, Angola, Mozambique and Nicaragua "a great moral issue of our time" and said, "The real question we should be asking is not, 'Will we give aid or no aid?' but 'Will we give enough aid so freedom doesn't die, that freedom can win?' The question Americans must ask . . . is 'Why not victory?' "