"This wouldn't be the president of the United States and the leader of the Free World, would it?" asked Rep. Robert K. Dornan (R-Calif.) of a caller yesterday afternoon while filling in as guest host of a nationally syndicated radio talk show from ABC studios here.

"How ya doing, Bob? What's a nice guy like you doing trying to be a talk host on such a nice show?" asked an unusually schmaltzy George Bush.

And for the next five minutes, in what WMAL news reporter Larry Matthews would later describe (off-air) as "a five-minute Republican love-in," the two politicians gushed over each other before an audience estimated at more than a million.

Dornan, a gravelly voiced former San Francisco radio and television talk show host, is substituting for conservative gab-master Rush Limbaugh, who is vacationing this week in the Bahamas. At one point during the two-hour show, heard locally on WMAL-AM (630), the conservative congressman told listeners that Limbaugh was aboard a cruise liner in the Devil's Triangle.

"You know, they told me 240 stations {would air the show}, and they couldn't keep me away from this building with a big stick!" Dornan told the chief executive with growing confidence. "Mr. President, I just want to tell you something on these 240 stations. That meeting we had in the Republican Conference this morning, all the Republican members of the House, you are our leader, our boss. We are solidly behind you. Some of the libs in the media are trying to drive a wedge between your pals in the Congress and the executive branch -- you, sir. And it's not working."

Dornan, possibly realizing that it was getting just a little too thick, added: "We are solidly behind you, but we also want to see big cuts in prolific spending. ... Dave Dreier {R.-Calif.} just called in and said the same thing. That you're our hero and our leader and we're with you, sir."

Bush, obviously enjoying the accolades, volleyed back.

"Well, I'm delighted to get that message. It was good seeing you, my good friend and early supporter, last night. And I just want you to know that this project of getting this enormous budget deficit under control is vital to our country. We've got to be sure that we reform the process and that is absolutely essential to get this spending under control. And American people know this. They're entitled to better... ."

And so it went.

At the Capitol, Dornan's staff was thrilled about both Bush's call and that their man was being heard on a live, nationally syndicated talk show.

"We are all pretty excited. We've been listening to him all week," effused Eric Nicoll, a legislative correspondent on Dornan's staff. "We've been getting a lot of calls from all over the country saying that they love him on the show."

Dornan spokesman Paul Morrell said Dornan saw Bush at a dinner for members of the Longworth House Office Building gymnasium Tuesday evening and asked the president to call the show "for a friendly chat" between 1 and 2 p.m. Morrell said the two have been close since December 1985, when Dornan was the first congressman to endorse Bush's presidential candidacy. Dornan later campaigned for Bush in 34 states, Morrell said.

And there was excitement at WMAL, which has been barraged with phone calls from listeners since it added Limbaugh's show five weeks ago. "Hey, the president is listening to WMAL!" squealed Pat Anastasi, the station's news assignment manager. Anastasi added, "I guess WMZQ wasn't playing the right kind of music." During the 1988 presidential campaign, Bush told a national newspaper that he was a regular listener to WMZQ, the country music station here.

Dornan said he expects Defense Secretary Richard Cheney to call today to "tell you about the sad state of affairs of near chaos in the Soviet Union." And he said Vice President Quayle would call tomorrow to discuss his treatment by the media.