Senate Majority Leader George Mitchell urged Republicans Wednesday to permit a vote swiftly on the embattled nomination of John Tower to be defense secretary, but Sen. Bob Dole declared: "We don't want to prolong the debate - we want to win."

However, Sen. Claiborne Pell, D-R.I., who had been listed by some Republicans as a potential swing vote, announced he will vote against Tower because he has come to believe the relationships Tower forged with defense contractors after leaving government service pose "at least the appearance of conflict of interest.""In this case, I do believe it's in the nation's best interests for the president to make another choice," Pell said.

Mitchell, D-Maine, repeated his claim that the nomination will be defeated, and Dole did not directly dispute him. "We're not certain," he said. "It's going to be a very close vote."

The Associated Press survey indicates 48 Democrats and Republican Larry Pressler of South Dakota as either firmly opposed to the nomination or leaning in that direction, and 40 Republicans and two Democrats either firmly in favor or leaning that way.

Dole, R-Kan., said he had talked by phone earlier Wednesday with President Bush, who continues to support Tower. He said he would continue the effort to "attract enough Republicans and Democrats to support the nomination"

Dole and Mitchell thus set the stage for a fifth day of debate on the nomination, which has produced frayed tempers and unusual personal outbursts on both sides of the struggle.

Mitchell was asked if he is disturbed that the Senate may be damaged by the debate's increasingly bitter and personal tone. "Yes I am," he replied. "I think the way to end it is to vote. Letters are coming in saying, `Enough is enough.' "

Republicans now hope to convert other undecided Democrats, concentrating their efforts on a handful of lawmakers. These include Sens. Joseph Lieberman, D-Conn.; Charles Robb, D-Va.; Bennett Johnston, D-La.; and Lloyd Bentsen, D-Texas.

Mitchell told the Senate Wednesday that the central focus of the debate is the claim by Republicans that Tower should be approved "because the president is entitled to have his own man."

But he said Tower himself, while serving in the Senate, repeatedly voted against presidential nominees "simply because he disagreed with some of their positions."

Mitchell suggested many senators of both parties have reversed position on the proper stance to take on nominees because of the shift of the political winds.

"I predict that if ever and when there is a Democratic president they (Republicans) will reverse position again," he said.

At the White House, Sen. Alan Simpson, R-Wyo., the deputy GOP leader, said after a meeting with Bush that an "excellent opportunity" remains to pick up the Democratic votes needed to push the nomination over the top.

Dole left open the possibility of asking the Senate to permit Tower to answer the allegations against him from the floor of the chamber.

But Democrats said that would set "an awful precedent" for future confirmation battles and Dole appeared to concede he would make that move only as a last resort.

Mitchell called it a desperation tactic. "I do believe enough is enough," he said. "Why will the proponents of the nomination not permit a vote?"

On Tuesday, Sen. Christopher Dodd, D-Conn., recalling Tower's vote against the Senate censure of his father for improper use of campaign funds 22 years ago, said he would vote for confirmation.

Dodd said that although he and his family will be "eternally grateful" for Tower's defense of the late Sen. Tom Dodd, D-Conn., his decision did not rest on personal considerations.

He said that reading the file of the FBI investigation into Tower's past he believes evidence is too thin to support a vote to bar the former Texas senator from becoming defense secretary.