He was the comeback candidate. No one took more beatings. No one went to the mat more often. No one bounced back with more tenacity and grace.

Even in the end, he didn't want to quit. He agonized over it for days. But finally, he accepted what the numbers told him -- that he was finished.

And yesterday, in a hotel ballroom in Houston, George Bush conceded the 1980 Republican presidential nomination to former California governor Ronald Reagan and ended his two-year quest for the nomination.

"I see the world not as I wish it were, but as it is," Bush said. And he sent a telegram to Reagan congratulating him on a "superb" campaign and offering his "wholehearted support" in the fall campaign.

Bush said the decision went against "my every gut instinct, my every bit of training."

"I have never quit a fight in my life," he said. "But throughout my political career, I have always worked to unite and strengthen the Republican Party."

Bush said he would urge delegates pledged to him and any elected in the final round of primaries next Tuesday to support Reagan at the July Republican National Convention but said again he had no interest in being Reagan's running mate.

"The No. 1 priority for Republicans in the fall of 1980 is to unite to save our country from four more years of Jimmy Carter's weak, directionless, incompetent leadership," Bush said.

In California, Reagan called Bush "a superior campaigner," and said he was "most grateful for his expression of support for my candidacy and for his pledge to work for unity in the party."

Republican National Chairman Bill Brock greeted the news jubilantly. "We have a Republican nominee . . . Ronald Reagan will be the standard-bearer for the Republican Party in 1980."

The Republicans, Brock added, enter the fall contest with a broader base, more supporters and a greater unity than any comparable race in the past 25 years."

Bush was the sixth and final major GOP challenger to withdraw from the race. The others quit after defeats. Bush, in the great irony of his candidacy, saw his campaign collapse after his biggest victory of the year, a 2-to-1 thumping of Reagan in last Tuesday's Michigan primary.

The media, especially two television networks, overlooked that victory to concentrate instead on Reagan's mounting delegate count. ABC and CBS said that night that Reagan had climbed over the magic 998 delegates figure needed for nomination; other news organizations said Reagan was on the brink.

Bush and his advisers claimed the two networks had done him in, but regardless of what they did all the numbers were against the former U.N. ambassador and director of the Central Intelligence Agency. They made the continuation of his candidacy all but impossible.

He had long hinged his candidacy on a strong finish in California, New Jersey and Ohio, the three big contests on June 3, the final day of the primary season. But his campaign was in debt -- $250,000 to $300,000 -- and "a widespread perception that the campaign is over," as Bush put it yesterday, dried up the flow of new money.

His advisers had budgeted $1.25 million for the last three states, of which $250,000 has been spent. Bush didn't have money to pay his staff, or for the last week even to charter a campaign plane.

Even after last Thursday, when Bush abandoned his efforts in California, projections showed that he lacked the money to wage anything more than a skeleton effort in New Jersey and Ohio without going another $200,000 to $300,000 in debt.

And it was for financial reasons that Bush yesterday did not technically and legally end his candidacy, a move that his advisers feared might make him ineligible for federal matching funds that they hope will help erase the debt.

The delegate numbers were even more devastating.ABC and CBS put Reagan over the top last Tuesday. United Press International, whose scorecard is used by The Washington Post, put him over with 1,001 delegates this past weekend. The New York Times likewise has now said Reagan has enough delegates for the nomination, although in all cases some of those delegate numbers are projections of what is likely to be the outcome in caucus states that have not yet finished their process.

Even Bush conceded Friday that Reagan would surpass the 988 figure in the next round of primaries. But he clung to the hope that somehow he could continue on and that many of the 49 percent of the delegates to the GOP convention who were not legally bound to a candidate would flock to him after June 3.

"My decision is a very practical one," Bush said at the time. "Can I get the wherewithal to do what I want to do -- to fight on. Or is it more graceful and more supportive in an obverse way to my supporters to say, 'It's all over'?"

"I made a point," he said Friday. "I have won in the northeast. I have won in the industrial Midwest. And it is very tough for the Republican nominee to win in the fall without these states."

He made the decision that it was all over after meeting two days with his family and closest advisers in his Houston home. He had so much trouble stopping that when his press secretary last saw him late Sunday, he said Bush hadn't made up his mind.

That Bush was the last surviving GOP challenger is one of the great political success stories of the 1980 campaign. More than anything else, it is a tribute to the skillfull management in his campaign and his tenacity as a candidate.

No candidate was more underestimated by his opponents. No candidate was written off more often by those he called the "mournful pundits." And no candidate campaigned longer or harder.

Bush, 55, began his campaign two years ago as an asterisk in the polls, adopting the same strategy another longshot, Jimmy Carter, had four years before. In addition to time, Bush had two great strengths: his energy and his resume. His credentials were a campaign manager's dream: son of a Connecticut senator, athlete, war hero (he was shot down as a 19-year-old Navy pilot in World War II), Phi Beta Kappa graduate of Yale. Successful businessman (oil), Texas congressman, U.N. ambassador, envoy to China, Republican national chairman and CIA director.

But despite his experience, Bush was largely unknown to the public. He was always a longshot, far behind better known candidates like John Connally, Sen. Howard Baker (R-Tenn.), and Sen. Bob Dole (R-Kan.), in the polls. Campaigning nonstop with his large family, Bush recruited a highly regarded staff and built a surprisingly effective campaign organization. "I go where they aim me," he said at one point. "I have good people and I trust them."

He inspired a fierce loyalty among his strongest supporters. "I'm tired of being a pragmatist. I'm going with someone I believe in this time," said John McIver, a veteran political operative who became his Wisconsin chairman.

Bush's media adviser, Robert Goodman, called him "the American eagle," and after he won an upset victory in the Iowa precinct caucuses, he soared in the polls. But he came tumbling down after a disappointing showing in the New Hampshire primary.

The rest of the campaign was a roller coaster. Stunning defeats in the South, Illinois, Wisconsin and Vermont. Co. Comebacks in Connecticut, Pennsylvania and Michigan .

Always there were those who said Bush was finished. Always there were those who doubted his motives. First he was accused of being a stalking horse among moderates for former president Gerald R. Ford. Then he was accused of being interested only in the vice presidency. Bush steadfastly denied interest in the vice presidency and repeated it yesterday in his press conference. But his name can be expected to be more frequently mentioned as a possible Reagan running mate.

"You have to remember a lot of people who started out when I was nothing in the polls aren't here anymore,' Bush said repeatedly. "Losing to Reagan isn't that bad. The question is are you the alternative."

After Baker and Connally dropped out of the presidential race, and John Anderson announced he would run as an independent in November, Bush became that alternative. But it was too late.