Tower, 63, in a statement delivered at the Pentagon moments after his defeat, said he might "be harshly judged" but departs "at peace with myself, knowing that I have given a full measure of devotion to my country."
In a statement released during a visit to New York, Bush praised Tower for devoting "his life to service of country," and said "instead of the recompense of a grateful nation, John Tower's lot in the last few weeks has been a cruel ordeal. For this, I am truly sorry."
Bush said that while he respected the Senate's role in the decision, "I disagree with the outcome. I am also concerned by the way in which perceptions, based on groundless rumor, seemed to be the basis on which at least some made up their minds in judging a man well qualified to be my secretary of defense."
The President was expected to quickly announce a new nominee. The names being mentioned as possible successors included former Rep. Jack Edwards of Alabama; Sen. William S. Cohen (R., Maine); investment adviser Donald Rumsfeld, who headed the Pentagon under President Gerald Ford, and Norman Augustine, president of Martin Marietta Corp.
Presidential spokesman Marlin Fitzwater would not comment on the speculation, but said the White House was prepared to move fast in an effort to put behind it Bush's first defeat at the hands of the Democratic-controlled Senate.
Senate Democrats insisted that the rejection of Tower was not an effort to weaken Bush. Senate Majority Leader George J. Mitchell of Maine said, "From the bottom of my heart, this is not the case."
He also said he was confident that the battle would result in "no permanent, long-lasting damage" to relations in the Senate or dealings between the White House and Congress.
Sen. Sam Nunn (D., Ga.), the Armed Services Committee chairman who was regarded as the key to Tower's defeat, said, "I don't think anyone won this one. . . . It's certainly not a feeling of elation I have. It's a feeling of sadness." Nunn spoke in Philadelphia, where he was attending events for the Democratic Leadership Council.
Some Republicans, citing the extraordinary acrimony that marked the six days of Senate debate, warned that lingering bitterness will make it difficult for Democrats and Republicans to work together on other issues.
"We ought to hang our heads after what we've done to this good man," said Senate Minority Leader Robert Dole (R., Kan.). "America has lost a good public servant. The President has won because he stood by his man."
"Some of the hurt of this will not go away," predicted Sen. Rudy Boschwitz (R., Minn.). "Don't expect things to return to normal."
"This is going to be an embarrassment to the President all around the world," said Sen. Strom Thurmond (R., S.C.). "The leader of the free world can't even get a cabinet member confirmed."
It was only the ninth time in 200 years that the Senate has voted to reject a president's cabinet choice, and the only time it has done so early in a new administration. Bush has been in office for 49 days.
In his brief statement, Tower said no other public figure "has been subjected to such a far-reaching and thorough investigation nor had his human foibles bared to such intensive and demeaning public scrutiny."
"And yet, there is no finding that I have ever breached established legal and ethical standards nor been derelict in my duty," he said.
Tower said he intended to return to private life in Texas. He did not take questions from reporters.
The nomination was derailed by concerns about Tower's personal behavior - in particular, his drinking. A lengthy FBI investigation produced hundreds of pages of reports - many unsubstantiated - of allegations involving excessive drinking, which touched off questions about whether Tower was fit to
serve as defense secretary.
Few challenged his professional qualifications: as a former chairman of the Armed Services Committee and an arms control negotiator in the Reagan administration, the 63-year-old Tower was a recognized defense expert.
With the outcome clear yesterday morning, Dole abandoned an unprecedented plan to confirm Tower for only six months to let Tower demonstrate that he would honor his pledge to abstain from alcohol.
When Democratic opponents said they would not go along with the plan, Dole quickly conceded that "it's not going to change any votes" and dropped the idea after consulting with Tower.
The Senate roll call on Tower was unusually somber. Most senators were in their seats, rising to vote as their names were called. The gallery was packed with spectators.
Vice President Quayle presided and announced the result of the vote. Quayle could have voted only to break a tie.
On the confirmation vote, only Lloyd Bentsen of Texas, Howell Heflin of Alabama and Christopher J. Dodd of Connecticut broke Democratic ranks to support Tower.
Among senators from the Philadelphia region, Pennsylvania's two Republicans, John Heinz and Arlen Specter, and Delaware's William V. Roth Jr., a Republican, voted for the nomination. Voting against Tower were Democrats Joseph R. Biden Jr. of Delaware and Bill Bradley and Frank Lautenberg, both of New Jersey.