President Bush, moving swiftly to recover from the Senate's rejection of John Tower as defense secretary, Friday nominated Rep. Richard Cheney, R-Wyo., to head the Pentagon.

"Dick is a widely respected man of principle," said Bush, announcing the nomination exactly 24 hours after the Senate rejected Tower's nomination on a 53-47 vote. "I'm convinced that he's going to be a great leader of our nation's military forces.'Cheney, 48, was first elected to Congress in 1978 and currently holds the No. 2 spot in the House Republican leadership hierarchy. He was the White House chief of staff under President Ford.

The selection marked the first time that Bush asked a sitting House or Senate member to serve in his administration.

In 1987, Cheney gained some national attention by serving on the congressional committees that investigated the Iran-Contra scandal. He often played a lead role in defending former President Reagan's actions during the nationally televised hearings.

Cheney suffered heart attacks in 1978 and 1984. He underwent heart bypass surgery in August 1988 after a third attack.

But Cheney said Friday that he talked with his doctor just before the announcement and was advised that "there's absolutely no medical reason why I cannot undertake this assignment."

Bush, perhaps attempting to help ensure his new nominee will face no problems on Capitol Hill, tried Friday to put the bitter nomination fight over Tower behind him.

"Look, that's history," Bush said. "We're moving forward with a new nominee."

He added that he was completely satisfied that Cheney had nothing in his background that would cause his nomination trouble in the Senate.

"I believe that it will go very fast and I believe it will have smooth sailing," Bush said of the Cheney nomination.

Bush also refused to comment on a harsh speech that Vice President Dan Quayle gave in Indianapolis in which he attacked Senate Democrats for using McCarthyite tactics against Tower.

The president said he would not discuss comments he had not seen or heard. Nonetheless, he insisted that Tower's treatment at the hands of Democrats was unfair.

He also added that he took Democratic leaders "at their word" that the White House and Congress could move quickly beyond the Tower fiasco.

Reminded that he had said Tower was the most qualified man for the Pentagon, Bush said that "as of today, Dick Cheney is the best and proper choice."

Bush insisted that he had not considered any nominees besides Tower until it was clear his first choice would be rejected. Once he was turned down, Bush said, "I wanted to make a decision fast on this."

Cheney said his decision to accept the nomination was not easy but added that "when the president asks you to consider a proposition such as this one, you have to consider it seriously."

He added that he was first contacted about the job Thursday afternoon by White House chief of staff John Sununu and national security adviser Brent Scowcroft, with whom Cheney served in the Ford White House.

The president, asked about his promise not to deplete GOP ranks in the House and Senate, noted, "This is the exception that proves that rule."

Sen. Sam Nunn, D-Ga., chairman of the Senate Armed Services Committee, and the panel's senior Republican, John Warner of Virginia, termed Cheney "well known and highly respected by members of the Senate."