Vice President Bush was walking alongside the Rev. Jerry Falwell at the conservative southern preacher's college last month when he noticed that Falwell and the school's trustees were spoofing him; all were solemnly wearing the blue-and-white tie of the vice president's Ivy League alma mater, Yale.

Bush recalls laughing--the laughter of a politician who remembers that the right wing of his party did not back him for president or even vice president in 1980. Too much a Connecticut preppie, they said, with his millionaire daddy, those old school ties and multi-colored watchbands, not a true down-to-his-toes conservative like Ronald Reagan.

As Bush finished answering questions from Liberty Baptist's Young Republicans chapter, including one on why he does not oppose abortion, Falwell came on stage with a gift for him: a red, white and blue Liberty Baptist tie. Bush pulled off his tie and put on the one from Liberty Baptist. The audience gave him a standing ovation.

That scene was a high point for Bush in his 2 1/2 years as No. 2 man in the government, a sign that the staunch right-wing opposition that has dogged him so long and clouded his chances to be president may be softening. (Falwell later endorsed Bush for vice president in 1984.)

And there have been other good omens lately for Bush as he waits for the 72-year-old president to decide whether he will seek reelection.

Last week, in an unusually strong endorsement with the 1984 nominating conventions still more than a year away, President Reagan said that "when I needed someone of unquestionable leadership, loyalty and skill there is only one person I could or would choose again, and that's my partner and your vice president, George Bush."

"I believe Ronald Reagan will run," said a senior White House official. "But if he doesn't run, I think he'll put his arm around George Bush and say, 'The economy is improving, we've got the government off your backs, but there's more to be done, and here is the man to finish the job.' That's what the decision comes down to."

Even Bush's toughest conservative critic, Richard Viguerie, concedes that if Reagan does not run in 1984 Bush seems certain to be the Republican nominee.

"Yes, outside of Ronald Reagan running in 1984 he'll be the candidate," said Viguerie, who then quickly added: "But definitely not in 1988. Now is his best chance. A lot of people are off and running early for 1988. At the moment the conservative opposition to Bush is stymied, not focused..."

Bush's loyal performance as vice president has made him some friends among conservative Reaganites. The memory of his stabs at Reagan, including calling Reagan's tax-and-spending proposals "voodoo economics," during the 1980 campaign are distant now.

Bush's own record, moreover, is quite conservative. The former CIA director is as confirmed a hawk as Reagan on arms issues; he said in 1980 that he believed there is such a thing as a "winnable nuclear exchange." He has headed Reagan's regulatory reform effort and relishes telling audiences that consumer advocate Ralph Nader "is going down, and we're coming on strong." Still, some assess Bush as a moderate, and Bush has no emotional conservative constituency.

In fact, some conservatives charge it is mainly Bush's former campaign workers, including White House chief of staff James A. Baker III and communications director David R. Gergen, who are keeping Reagan from being Reagan. That attitude is not held in the White House; Bush is regularly described as an asset, drawing the moderate wing of the party into the administration and defusing minority and labor opposition by keeping lines of communication open.

He is not seen as a jealous runner-up, plotting overthrow.

"Well, I think you've got to know what you're not, and what you're not is president," Bush said as he flew on Air Force Two to Florida last week. "And also you know what you are, and what you are is an adviser to the president who has a fascinating job that everybody knocks but that everybody who is not president wants."

Bush has not become involved in the squabbling among White House aides, even though some were originally his people.

"I wouldn't do that," Bush said. "I stay out of all this, you know, posturing around . . . . When I volunteer something to the president, I don't share it with anybody else. Anybody else. So I stay out of the biggest, you know, most popular game inside the Beltway."

When Reagan was shot, senior White House officials noticed that Bush chose not to have his helicopter land at the White House and that there were no proclamations from the vice president like then-Secretary of State Alexander M. Haig Jr.'s embarrassing, "I am in control here."

"I must say some thoughts about his role if the president died crossed through my mind but not . . . no, my thought process didn't get ahead of the events . . . . It never occurred me that the helicopter from Andrews Air Force Base should land at the White House ," Bush recalls. "I'm very kind of normal. Maybe it is my elitist background laughter . I would never call the president by his first name. And if I'm not president I would not have my helicopter land on the White House lawn . . . . "

Bush, asked if he gives thought to the president's age, says: "I think the reason the age thing isn't thought of by me or others is the vitality of the man . . . . I am amazed at his physical strength . . . . "

Bush's most notable public contributions to Reagan have come with his trips abroad.

The London Times had, at one point, predicted that Bush's nuclear arms trip to Europe last winter would prove "useless." It later recanted, writing that "Mr. Bush provided a cogent answer to the red herring so skillfully trailed across the argument by Mr. Yuri V. Andropov . . . . "

When Bush returned to report on how the NATO allies viewed the U.S. position at the Geneva arms talks, White House officials said that he made a strong argument for an interim arms proposal to show American flexibility.

"He was smart," said one White House official, "he made himself an ally of the president and national security adviser William P. Clark, not a messenger from Europe. And he said, 'here is how we can turn around the momentum over there' . . . . It helped to turn the tide."

As close as Bush will come to confirming the story is to say, "I might have done that. That would be an example, and then he Reagan might agree or disagree. If he agreed fine, that would be his idea. And if he disagreed, nobody would know there was this difference. Because what a president should not have is visible differences with his vice president.

"He doesn't need the uncertainty that would come with a vice president going out and saying 'well, look, I recommended he do this on INF the Euromissile problem , and he didn't do it, and I think he made a big mistake.' "

"You've got to take him Bush seriously because the president takes him seriously," said Lyn Nofziger, who opposed giving Bush the vice presidential nomination. "George has played his hand very well. Some people think he's not effective because he doesn't sit in general meetings and get into disagreements with the president. If he did he wouldn't be in the meetings for long . . . . He hasn't done anything to get the president in trouble. He lobbies the Hill. And he has his shop under control; they aren't fighting the president's people."

White House officials now look at Bush's schedule to see how he can make further peace with the right-wingers who remain suspicious.

Bush, instead of the president, is scheduled to give the Evangelical Prayer Day address this year.

Most important, Bush appears to have won Reagan's trust. He has a private lunch with the president once a week; attends most meetings, including those of the National Security Council; sees the president daily, according to both men, and has an office in the West Wing as has only one other vice president, Walter F. Mondale.

"Well, now, I don't know what authority Mondale had with Carter," Reagan said in an April 29 interview with The Houston Post, "But we Reagan and Bush sit there as equals, except we both know I have to make the decisions."

In that interview, Reagan said that if he runs again Bush is his vice presidential candidate because "you don't break up a combination that's working." Reagan added, "I don't think that I can recall many vice presidents who have been as involved and much a part of things as he has."

"He Bush is very much a part of the decision-making machinery," said Baker, the White House chief of staff who managed Bush's presidential campaign in 1980. "He is included in the paper flow; he sees all the paper the president sees. He has carved himself out an operational role compatible with the president's staff. That is his view of the office's function. And it's correct."

People outside the White House also praise Bush. Sen. Paul Laxalt (R-Nev.), the general chairman of the Republican Party and a close and conservative friend of the president, said there has been no talk of dumping Bush. "He's been a 10 plus on a scale of 10," Laxalt said.

"There's no question he's handled the job well," said Rep. Dick Cheney (R-Wyo.), chairman of the Republican Policy Committee. "I watched Rockefeller under Ford, and I know the frustrations Ford had when he was vice president. Bush has a good sense of what the job is. Now there's the question of Bush and the presidency. You know anyone who's vice president thinks he got a shot at being president. Johnson did it, Nixon, so did Ford. Mondale is getting ready to try the same thing. It's the only reason to be vice president, but I don't see it affecting Bush's behavior. He's been loyal all the way."

Despite his high grades as vice president, Bush has failed to make his mark with the ultra-conservatives as a possible president.

When Reagan traveled to Houston last month, he found the Texas Republican Party in a fierce fight over the chairmanship. Reagan supporters were pushing out the head of the party because they considered him a Bush supporter and did not want him in control if Reagan doesn't run.

"If Bush is ever the Republican candidate, there will be a blood bath between the moderates and the right wing of the party," said a professional political analyst for the Democratic National Committee. "Bush will have to referee it. It's his burden to bear."

"Bush's support comes from corporations, Wall Street, the Yale and Princeton alumni association," said Viguerie, whose Conserative Digest's April issue reported that conservatives across the nation place Bush fourth in their choices for president if Reagan does not run. Bush (4 percent) came in behind Rep. Jack Kemp (34 percent), Sen. Jesse Helms (25 percent) and Rep. Philip M. Crane (13 percent).

"George Bush is not a conservative," said Viguerie. "Liberals think he's right wing because he's not a socialist like Ted Kennedy. He has a big corporate America background. His view of trade with the Soviets is that it's good for business. That's not conservative. He's not a friend of fundamentalists and Christians on moral issues, prayer in school, abortion. If Ronald Reagan is in the White House raising taxes, you can imagine what Geoge Bush and his crowd would be doing."

Much of the criticism of Bush is tinged with class tension, a feeling of animosity toward Bush's wealthy upbringing and life style.

"Those critics," Bush said when asked about class divisions in the party, "never run for election. Sam Rayburn said not one of them would run for sheriff. They never lived in Texas. They never fought in combat for their country . . . . They never started a business, in a tough business, tough days, made it work, employed a lot of people. So I don't get troubled by that."

The right-wingers fear the Bush crowd is shadowing Reagan, waiting to snatch power. The anxieties prompted Nofziger to write last November: "I think it's important that the next presidential election be a Reagan-Bush campaign, not a Bush-Reagan campaign."

Nofziger, like Viguerie, is concerned that, should Reagan announce he will not run, Bush will almost automatically become the party's candidate. "There'll be a lot of resentment in the party if Reagan tries to shove Bush down their throats," said Nofziger. Nevertheless, he added that Bush "has been loyal and done a good job as vice president. The question is what does he believe. No one knows what George Bush has been thinking or doing. He's been low-profile. You don't know that he's a Reaganite."

Suspicion of Bush's ambitions are fueled by his frequent travels. He has traveled 344,364 miles as vice president, covering all the states. And he has raised over $28 million for Republican candidates in the last two years.

"If somebody wants to read some interpretation in it, fine," Bush said. "But part of my job is to take the message out there . . . . If it somehow spills over on my plate, fine. But that's not what I'm trying to do . . . . "

Later Bush said: "You're never going to believe this, but I honestly am not thinking that far down the road. And I don't know what'll happen in '88. And I know nobody believes that, but it's absolutely true."

Despite concern from right-wingers that Bush is moderate, Richard Wirthlin, Reagan's pollster, finds that "Ronald Reagan, George Bush and the Republican Party are pretty much viewed as one in the same package."

According to Wirthlin, Bush is strong in the Northeast, among "up-scale Republicans," and also "shows a great deal of strength in the South," and Kentucky, Tennessee, Florida and Texas.

While Reagan runs better among blue-collar voters, Wirthlin said, Bush does best among Republican conservative college graduates, persons at least 65 and married men. They do equally as well among conservatives. Bush, whose son is married to a Mexican and who calls his grandson "their brown baby," does not attract any more minority-group voters than Reagan does, according to Wirthlin's data.

Bush makes the point that he is not using the office of vice president to make himself well known: "I always had the feeling that Mondale had the approach . . . . He said, 'I was in on everything; I was advising; We were a good team. P.S.: I wasn't with him on issue A, B or C' . . . . I mean I couldn't do that to Reagan. I couldn't, and that doesn't mean I'm devoid of my own thoughts or something like that. But to go back and revise it and say, 'Yeah, I was there but I told old Ron he shouldn't have done this'...uh-uh."

"We really have to coax him Bush to do TV," said Richard Williamson, assistant to the president for intergovernmental affairs, after Bush appeared to discuss the administration's policy in Central America.

"If he was like Mondale was with Carter, you wouldn't be able to keep him off the tube," he said. "He's much more low-key in public, but he's by the president's side . . . . If the president decides not to run, the vice president is clearly in the best position of any candidate. I doubt Ronald Reagan officially will endorse anyone. But in the very unlikely event he decides not to go, George Bush will have a lot of friends in the White House.