OLUMBIA, S.C. - Two months after he lost a key primary in this state, Senator John McCain apologized yesterday for betraying what he called the single most important principle of his bid for the Republican presidential nomination.
In an unusually self-critical speech, McCain said he had not spoken his true feelings during the campaign when asked his view of the Confederate battle flag flying over the state house here. He did not tell reporters at the time that he believes Confederate soldiers ''fought on the wrong side of American history'' and that the flag should be taken down, he said yesterday.
He said he considered those omissions ''unprincipled'' and that he fully deserves the criticism that he expects to rain down upon him because of it.
The lapse has so eaten away at the senator, aides said, that he returned to South Carolina for the first time since his drubbing in the Feb. 19 primary.
''I feared that if I answered honestly, I could not win in the South Carolina primary. So, I chose to compromise my principles. I broke my promise to always tell the truth,'' he told members of the South Carolina Policy Council here.
While some of McCain's supporters here saw McCain's mea culpa as a testament to his integrity, others were incensed by what they saw as a betrayal.
''He abused, misled, and lied to the people of South Carolina in order to accomplish a political goal,'' said state legislator Jake Knotts, who was a member of McCain's steering committee. ''I'm ashamed of the fact that I took him at his word, and took him around this state, portraying him as the new horizon in politics, and then he betrayed the people just like he did.''
McCain responded by saying Knotts ''has every right to feel that way.''
Throughout the campaign in South Carolina, McCain tried to avoid being drawn into the dispute over the Confederate flag. At various times, he said he understood each side of the debate, that conservative voters might see the flag as a symbol of heritage, and that minority residents would see it as a symbol of racism and slavery, but that he thought the matter should be left to the people of South Carolina.
He often cited the fact that his own ancestors had fought as Confederate soldiers and that their service was honorable and should be recognized. Yesterday, however, he said his view of his forbears was more complicated than that.
''I don't believe their service, however distinguished, needs to be commemorated in a way that offends, that deeply hurts, people whose ancestors were once denied their freedom by my ancestors,'' he said. ''They fought to sever the union of our great nation, a cause that would have terribly harmed America, perhaps irreparably, and, for a time at least, perpetuated the grave injustice of slavery.... That, my friends, is how I personally feel about the Confederate battle flag. That is the honest answer I never gave to a fair question.''
McCain said the flag should be removed from the Capitol, but said he found it encouraging that the state seemed to be resolving the situation itself. Last week, the state Senate voted to take the flag down from the state house dome and move it to a nearby Confederate soldiers' monument.
The NAACP, which began an economic boycott of the state at the height of the controversy, opposes the relocation, arguing that the new location will make the flag even more prominent.
Yesterday's apology was not out of character for McCain. The senator has taken many a trip to the public confessional. He has apologized repeatedly for his role in the Keating Five influence-peddling scandal, for example.
Yesterday, McCain said he was not seeking forgiveness.
''I will be criticized by all sides for my late act of contrition,'' he said. ''I accept it, all of it. I deserve it. Honesty is easy after the fact, when my own interests are no longer involved. I don't seek absolution.''
He added his hope that, ''in the end, my character is judged by the totality of my life, and not by its flaws alone.''
Richard Quinn, one of McCain's South Carolina advisers and a founder of the conservative Southern Partisan magazine, said he thought McCain had been far too hard on himself.
''Everything he said was factual,'' Quinn said. ''When he was asked `How do you feel personally?' he held back. I think he was harsh on himself to say that was dishonest. He was just not forthcoming.''
''It would have been easy for him to just stay out of it, but he came back, so I have a lot of respect for him,'' said Vince Ellis, a Republican candidate for Congress who is African-American. But Ellis conceded it would have sent a more powerful message if McCain had risked being completely honest.
''It would have made it easier for minorities to be comfortable with this party if he had done that,'' he said.
Knotts was less forgiving.
''If he'd lie on the campaign trail, then he's no better than Bill Clinton,'' the legislator said. ''He'd lie in Washington or in the White House.'' Still, he said, he would probably have supported McCain even if he'd known his true views on the flag.
Texas Governor George W. Bush has stuck to his view that the flag controversy is a state matter. The campaign of Vice President and presumed Democratic nominee Al Gore yesterday called on Bush to clearly state his personal opinion on the flag.
McCain said his mea culpa was not meant to put pressure on Bush, who has been trying to appeal to moderate voters. Several of McCain's former supporters have argued that Bush would capture moderate voters by inviting McCain to be his running mate, and Bush recently said he had not ruled out the Arizona senator. But McCain said yesterday: ''I do not seek and do not want to be considered for vice president of the United States. I would categorically state to Governor Bush ... that I do not wish to be asked.''
