WASHINGTON (AP) _ Trounced in Iowa and desperate for victory in New Hampshire, George Bush - the fellow who talks up loyalty about seven times a day - sure could use some help from the boss. If Ronald Reagan ever wanted to give his vice president a boost, the clock is ticking.

From the Oval Office comes ... silence.

In the White House and throughout the political community, there is a general belief that Reagan will continue to remain mum, as he has long promised he would, refusing to endorse anyone for president until the GOP nomination is settled.

''I know there are some of the vice president's supporters who have assumed that at some point, the president would play lifeguard. I don't think so,'' said Mitchell Daniels, Reagan's former political director.

''I take the president at his word, that he does not want to meddle or appear to meddle in the nomination process,'' Daniels said. ''I think he's trying very hard and carefully to live up to the vow of neutrality that he's taken so long.''

Eddie Mahe, a political consultant, said that neutrality is the only position Reagan can take without splitting the GOP, and that the president wants to be a unifier.

Noting that Reagan is still very popular in New Hampshire, Mahe said a Reagan endorsement would be very helpful for Bush.

''It also would be extremely divisive and, over time, would not be helpful,'' Mahe said. ''It would be destructive to Ronald Reagan's agenda in the Senate. Remember, a majority of Republican senators are supporting Bob Dole, not George Bush.''

If Reagan endorsed Bush, other Republican candidates would have to go on the attack against them. ''You can't sit there and let someone as big as Ronald Reagan endorse your rival,'' Mahe said. ''You have to fight back.''

Daniels recalls being with Reagan at private meetings when political associates of 30 years or more asked the president about his preference. Daniels said Reagan ''was very careful to stay on the straight and narrow'' and refrain from tipping his hand.

Would Reagan let Bush sink, if it came to that? ''Yes,'' Daniels predicted.

''It's important to remember the extent to which Ronald Reagan has unified or homogenized the Republican party,'' Daniels said. ''Reaganism has become the party dogma. Everybody in the race is a Reagan supporter; nobody is a Reagan opponent.''

No one doubts that Reagan and Bush have a special relationship and are good friends.

The president has called Bush the best vice president in history and, following the Carter-Mondale model, has provided him with extraordinary access to information and meetings.

''But I have to remain neutral until the decision is made by the party as to who their nominee will be,'' Reagan said two months ago in his most recent comment on the issue.

With his third-place finish Monday night in Iowa, Bush is counting on a victory in the New Hampshire primary next Tuesday to keep his faltering campaign alive. All the candidates are going all out, seizing on anything they can for an advantage.

Bob Dole, the vice president's chief rival, got a letter from Reagan, praising him for voting for Contra aid. Dole brandished it around New Hampshire on Wednesday as a sign of his closeness to Reagan.

Bush got lunch Wednesday with the president, as he does once a week when he's in town. In a gesture of even-handedness for the Dole letter, the White House released a picture of Reagan and Bush - something it hasn't done before.

Did Reagan offer Bush any soothing words at lunch about Iowa? After all, Reagan was in the same boat in 1980, a loser to Bush in the Iowa caucus that year.

''We didn't go into the campaign,'' Bush replied. ''He's staying neutral.''

For the record, Bush's staff says he's happy with Reagan's neutrality. ''We don't expect anything different from that to occur,'' said Stephen Hart, a Bush spokesman. ''The vice president agrees with that position of neutrality, thinks it's appropriate.''

Taking their lead from Reagan, White House officials are keeping out of the presidential race.

''Our problem is, we're all hypersensitive to be neutral,'' said Fitzwater. ''The president's neutral; we're neutral.''

However, White House officials who insisted on anonymity let it be known that Dole wasn't the only person to get a letter from Reagan on Contra aid.

Every member of Congress who voted with the administration - 262 in all - got a similar letter.

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EDITOR'S NOTE - Terence Hunt has covered the White House since 1981 after following the presidential campaign of Ronald Reagan.