Pat Boone is in the back seat, his wife and his raisins nearby, when he gets on the subject of how he makes people sick.

"This guy went around on college campuses and asked them what they thought of me," he begins, the chauffeured LTD splashing down the street east of the White House, "and he came back to me and he told me, 'You know, people have only two reactions to you. They either say they love you -- or that you make them sick. They'll just say, you make them -- '"

"Look," interrupts his wife, Shirley. "A helicopter is landing on the White House lawn." "The president is coming back from Texas," offers the chauffeur.

"' -- sick'," says Boone. "They'll say I make them sick."

He sighs, the bracelet-draped hand resting on the brown double-knits, which set off his white cord jacket, which matches his white buckskin saddle shoes. Really, those are the shoes he wears. Rolling Stone meant it when they put him on the cover and called him "The Great White Buck."

But now Jimmy Carter's helicopter has passed from sight and consciousness.

Boone, en route from one cause to another, is on to the Washington Hilton and another story about how he made Gloria Steinem sick when both were on the Dinah Shore show.

"When I left the set, I said, 'Gloria, I really enjoyed meeting you and talking with you.' And she said, 'Give my regards to the ayatollah.'" Boone looks out the window.

"She was putting me in his league," he sighs later, "like I was just some incredible relic from bygone days."

Celebrities who support causes come regularly to Washington. The causes can take the form of no nukes or solar power or whales, but usually it's just one at a time.

Yesterday, Boone was here for three: Cambodian relief, Rep. Bob Dornan (R-Calif.) and Jesus.

"Praise the Lord," he said at the Jesus event and almost everywhere else. In transit, too.

The day started in the White House East Room. Boone, fresh from The Club Rene in Morgan, N.J. (two late shows Sunday) gave Rosalynn Carter a plaque from his Save the Refugees Fund, then was whisked off to sing in the drizzle for 10,000 Youth for Jesus at RFK Stadium, then was whisked off to the Washington Hilton for a Save the Refugees dinner, then was whisked off again to McLean for the fund-raiser for Dornan.

Along the way he ate: half a box of Sunkist raisins he kept in the back of the chauffeured car; two brownies as he left the White House, and three olives as he entered RKJ Staudium. His wife says he noshes a lot.

He also dry-brushed his teeth (the yellow toothbrush was in his breast pocket) and changed from white buck to black tux. The golf-course tan and hair, sculpted perfectly over each ear, remained exactly the same.

This is how he answers those who say he is another celebrity who backs causes and doesn't mean it: "A lot of good things need to be done." And as for his support of Jesus:

"It's the least commercial thing you can do. It would be more commercial if I were supporting a convicted rapist. People don't realize that when a performer does this he loses most of his former audience and the new audience is a fickle kind of crowd, so if they don't like something you do, they write you off real quick. It's a suicidal thing for a performer."

Still, Boone, 45, has been around a good long time, and as he points out, still inhabits the same Hollywood mansion. Through the 20-year career that he swears began when he sang to his cow, Rosemary, while milking her back in Tennessee, this all-American boy has not only backed Jesus, but also milk, acne cream, Richard Nixon and now prayers for the Aytollah Khomeini.

"Jesus said 'Pray for our enemies,'" Boone tells the hundred or so people at the refugee dinner. "Now, that's not a natural thing to do. But since this has happened, there have been all sorts of things that have happened in Iran. There have been six earthquakes and the ayatollah has had one heart ailment."

In yet another car ride, this one to the Dornan fund-raiser, he explains what he means. "I'm not saying we're supposed to say, 'God, get him!' We're supposed to pray to God to bless him. Now how God accomplishes that is up to him."

Soon after, he pops ot of the car at the home of Richard Viguerie, the conservative direct-mail wizard who is holding the fund-raiser for Dornan. Dornan, called the "Great Right Hope" of Hollywood Republicans grabs Boone amid a lot of flashbulbs and backslaps at the door. Then Boone speeds downstairs to a crowd of admiring women.

"Milk image," says Dornan, who stands and watches. "See, they just like looking at him. I think it's because he's so darn clean in a world that's gotten so crummy around the edges."