Rich Little, America's best-known impressionist, is rooting for Vice President George Bush to be the next president, but politics has nothing to do with his preference.

Little, who is Canadian, merely prefers Bush over the Democratic presidential candidate, Massachusetts Gov. Michael Dukakis, because Bush is easier to mimic."If either Bush or Dukakis wins the presidency it will be an upset," he said. "Both men have speech peculiarities that help a mimic impersonate them. Neither one is easy, but Bush has the more recognizable voice.

"Bush speaks somewhat nasally, and he never finishes a sentence. Dukakis speaks in short little sentences that fall off at the end.

"As whining as Bush is, he still punctuates his words. He accentuates verbally when he talks. Dukakis doesn't emphasize words at all. He gives each one the same weight, which is unusual and undramatic.

"For an impressionist, Dukakis is the kind of guy you want around when you want to be alone. It wouldn't surprise me if he had a charisma bypass."

Little has been doing impressions of American presidents for about two decades. He said John F. Kennedy was his favorite subject.

"Kennedy's Boston accent and his gestures were really easy," he said. "Jimmy Carter was a good one, too. His Cheshire cat grin helped, going along with the clipped Southern accent. And, of course, we used jokes about his brother Billy.

"Ronald Reagan was tough to get a handle on at first. But his physical movements and the way he turns his head helped create a physical image. And his `Well, ugh' vocal mannerism was easy.

"In the beginning Reagan was difficult because he had developed a bland delivery from his movie days.

"The most bland of all was Jerry Ford. He was very hard to mimic.

"On the other hand, Richard Nixon was a cinch, a cartoon. In fact, most people think of me in terms of doing Nixon. The slight physical resemblance helps."

Little also has done impressions of Dwight Eisenhower and Lyndon Johnson, both of whom he says were not particularly difficult.

"The longer a president stays in office, the more he develops voice characteristics and facial tics," Little said.

"They have to speak so much under pressure for the cameras and microphones that they begin to fall into predictable patterns. These habits start to develop within months."

Little has collected his presidential impressions in a new home video, "One's a Crowd," that will be on sale later this month. It features a game of Trivial Pursuit being played by four presidents: Reagan, Carter, Nixon and Ford.

Another hilarious highlight is his impression of Jack Nicholson as president, holding an off-the-wall news conference.