Texas Gov. George W. Bush's allies among the GOP governors say they are prepared to help try to prevent Arizona Sen. John McCain from exporting his rise in New Hampshire to other early primary states and see Bill Bradley as the Democrats' stronger general election candidate in 2000.

All but a few of the GOP's 31 governors have endorsed Bush's candidacy in the Republican nomination fight, but for good measure, the Republican Governors' Association (RGA) offered an institutional endorsement of the Texas governor during a three-day meeting here this week.

The endorsement, unprecedented for a party committee at this stage of a presidential race, is largely symbolic. It will bring no additional resources to the Bush campaign, for example. But it is an indication of the degree to which governors, who formed the core of Bush's early support and helped fuel his campaign at the beginning of this year, are willing to use their muscle and prestige to help him win the nomination.

Oklahoma Gov. Frank A. Keating, the outgoing RGA chairman, said the group's endorsement was not related to McCain's emergence as Bush's principal challenger. But he suggested that if the effect is to slow McCain's progress, all the better.

"Politics is momentum and any additional momentum we can provide George Bush's candidacy, we wish to provide," Keating said. "If we can endorse him in a new and creative way every day we would do that."

Republican governors hold power in states with enough electoral votes to win the presidency, a clear advantage for Bush if he wins the nomination. But Democratic governors are in charge in Iowa, New Hampshire and South Carolina, the three states that will set the early tone for the GOP nomination fight.

Still, Bush can count on assistance in those contests from his fellow GOP governors, particularly those in neighboring states. Massachusetts Gov. Paul Cellucci said he has begun to supplement the Bush New Hampshire organization with volunteers from his state and expects other governors to do so in other states with early primaries. "We're already sending troops up to New Hampshire and we'll continue to do so," Cellucci said.

Pennsylvania Gov. Tom Ridge said governors also plan to stump for Bush in the early states. "When called upon to campaign, we go," he said. "You'll see a lot of George's friends in Iowa, New Hampshire and South Carolina."

Most of the governors said they doubt McCain can convert victory in New Hampshire or South Carolina, the two states where he has concentrated his resources, into broader support elsewhere.

"I think he can give Bush a real run in two states, New Hampshire and South Carolina," said Wisconsin Gov. Tommy G. Thompson. "But how do you translate that into a national campaign? . . . There's no way I see you can catapult victories in those two states."

But if McCain wins either or both of those states, Bush's gubernatorial allies in two other early states, Virginia and Michigan, say they will block McCain by delivering their constituents to Bush.

"I think Senator McCain is a good candidate, but I don't think he has yet obtained traction in Virginia," said Gov. James S. Gilmore III. "There's no reason to believe that he will, either."

Michigan Gov. John Engler was even more dismissive. The Arizona senator, he said, has "nothing" going in his state. In contrast, he noted that Bush recently announced a 250-member leadership team in Macomb County, a key battleground in general elections. "We're spending time preparing for [the primary on] February 22 but also hoping that as we do that we're laying the foundation" for the general election.

Bush's gubernatorial supporters said they do not believe McCain's surge in New Hampshire caught Bush by surprise, but said Bush will have to redouble efforts in New Hampshire to avoid an embarrassment. "What it suggests is there has to be a continued commitment to an awful lot of hard work and making one's self as available as one can be to be cross-examined and to participate in a process which in New Hampshire is very personal," said Montana Gov. Marc Racicot.

Looking toward the general election, the GOP governors said the traits Bradley has demonstrated in his challenge to Vice President Gore suggest that he could be a more formidable candidate in the fall of 2000. But several said Bradley is moving too far to the left in his primary campaign and risks giving up the middle ground.

Thompson was among the most emphatic in arguing that Bradley posed a bigger general election threat: "I just think that Gore has so much of the Clinton problems that he's saddled with that there's no way he can be a credible candidate."

Utah Gov. Mike Leavitt said, "You have to respect Bill Bradley as a very astute campaigner who has some public appeal. He's got some automatic star power to some people politicians don't generally reach out to."

Gilmore said neither Bradley nor Gore worries him. "Both are so far left they're way out of the mainstream," he said. "I'm confident that a strong candidate who has solid conservative backing like Governor Bush will win against these extremists."

Keating said that Gore looks like a weaker general election candidate because he "is joined at the hip to that unfathomably bad human being, Bill Clinton." But like Gilmore, he said Gore and Bradley are twins on most issues.

"Bill Bradley's a tall Jerry Brown. He's very liberal but very decent," Keating said. "Al Gore is a manicured Michael Dukakis. He's very decent, but very liberal. I think the two of them in a contrast with our candidate will pale by comparison."

CAPTION: GOV. FRANK A. KEATING. . . "politics is momentum"