What a varied collection of political has-beens and will-bes you could find calling on Menachem Begin last night.

For two hours the prime minister stood at the entrance to Israeli Ambassador Ephraim Evron's living room, grabbing hands from the outgoing administration that brought him peace and the incoming one that means, like his own future in upcoming elections, uncertainty.

The outlook, as he sees it, for the Middle East peace talks?

"That is the $64,000 question," he responded. "I don't know." And Ronald Reagan? "I hope he will be friendly," he replied, carefully. "He said he would be friendly."

Limbo was clearly the buzzword last night for a curious mix of Republicans and Democrats who came to a reception honoring Begin's unofficial visit to the United States. Today, he is scheduled to meet with Jimmy Carter. He won't be seeing Reagan, because Reagan thought that would be improper before Jan. 20.

The reception was a classic transition party -- the kind where beating around the bush and political Pollyannaisms come along with the fruit trays. Who wants to offend somebody who might give you a job?

Among the will-bes:

Sen. Howard Baker (R-Tenn.), the man Ronald Reagan want to be Senate majority leader. "I've hardly stopped smiling," said the senator. He didn't let up last night.

William Van Cleave, coordinator of Reagan's transition team at the Pentagon. Nope, said this former Pentagon official and Reagan's senior defense advisor during the campaign, he doesn't want to be secretary of defense. "Too senior a position for me," he explained. "I'm just a junior staffer."

Arthur Burns, former chairman of the Federal Reserve Board. Back in action again with the same pipe, same bushy eyebrows that appear to rise on cue when addressed with: And just what will you do for the new administration?

"Oh, help a little now and them," came the response. Then somebody pointed out that there certainly were an awful lot of Democrats around, like at his elbow.

"I can get along with Democrats," he said. "They're people, nice people. Some of them."

Raymond Tanter, a University of Michigan political science professor and Reagan's Middle East expert; David Weinstein, director of the Republican National Committee's Out-reach Program, which acts as liaison between the RNC and the Jewish community; and Daniel Graham, the former director of the Defense Intelligence Agency and now a Reagan military adviser.

And economist Alan Greenspan, too, who whisked in and out faster than Jimmy Carter lost.

Then there were the has-beens, among them Secretary of State Edmund Muskie, Treasury Secretary G. William Miller and Sol Linowitz, Carter's special envoy to the Mideast. He wasn't in the mood for discussing his future.

"I really don't want to get talking about things like that at this party," he said.As for the future of the Mideast peace talks, he only remarked that "it's too early yet."

Here's what Miller said about Carter's defeat: "These things happen."

And here's what Muskie said about Reagan's decision to stay out of foreign policy until after the inauguration: "I understand his position. We've already had some confusion as to who speaks for foreign policy. Why add another voice?"

Muskie took his usual cautious attitude about the hostages, saying only that the Iranian response to the U.S. response to their demands for releasing the captives "may take a little while. But they certainly are being fully presented with a documented proposal . . . it's comprehensive, it's thoughtful and it's positive. The question is whether they think that's the limit to which we can go."

Generally, the has-beens and will-bes made grand attemps to act like adults and be pleasant to each other, efforts made easier by conversations consisting of not much more than cocktail party niceties. These always occur at official after-hours functions, but last night were especially evident because no one knew enough about the political future to say anything of much substance.

Speculation about what Reagan might do for Israel centered on his campaign statements and the assessments of his soon-to-be cohorts. The Israelis, Howard Baker said, "have a staunch friend in President-elect Reagan. And they have a staunch friend in me."

But nobody knew for sure.

"It's a terrible time," said Miller. "No juicy tidbits."

Much more absorbing, then, was just watching the crowd patterns. Or, watching who and how many were collecting around whom -- one sure way to gauge power in this town. Over by the bar you could have found Graham, Reagan's conservative military adviser, telling jokes to a crowd of Israeli embassy officials.

"And so then I told her that if Israel hadn't been a little bit military, there wouldn't be an Isarel," said Graham, who has a shock of white hair that sticks up in a front cowlick.

"Har, har, har," said the embassy officials.