As the Reagan-Bush debate droned on in the gym, the Grand Old Party was erupting in revolt in the band room.

John Anderson, Howard Baker, Philip Crane and Bob Dole -- shut out from the debate of the front-runners -- were lambasting in angry unison at George Bush, charging that he alone had kept them from joining the debate.

They were charging that Bush had twice refused to meet with Reagan and them in the confused moments of negotiation and discord that preceded the debate.

And off to the side, as the candidate spoke, stood an unaffacing young woman who was about to report what may be the most damaging quote of all. She was Eleanora Kettler, daughter of candidate Anderson, and she said she had managed to get herself right next to Bush and Ronald Reagan as they walked into the debate site in the gymnasium at Nashua Senior High School.

She said that Bush told Reagan: "I'm not going on unless this goes as planned. I worked too hard for this."

And she said Reagan replied to Bush: "What was that you said at the debate (last Wednesday in Manchester) about how all of us were winners because the debate was taking place?"

The joint attack on Bush came at the climax of one of the most confusing days in recent Republican politics, a day Bush may long remember with regret. d

The controversy began in the early afternoon, when Reagan decided -- according to his staff -- to broaden the debate to include all challengers, since he had agreed to pay for the event and it was he who had borne the brunt of the criticism from the candidates who were left out.

Bush's advisers tell it differently -- they say that Reagan telephoned the Nashua Telegraph, the newspaper that had originally scheduled the two-man debate, and that Reagan told the Telegraph he was going to pull out of the debate if it would not be broadened to include all candidates.

Only the editors and the publisher of the Nashua Telegraph know which version is correct -- but in the midst of all the confusion last night, the newspaper officials were telling the press only "no comment."

as 1,500 persons waited in the gym, a drama of sorts was going on in the corridors. In one, next to multicolored school lockers, stood the Reagan aides. Around the corner stood the Bush aides. Telegraph executive editor Jim Breen and publisher J. Herman Pouliot were shuttling back and forth in between.

At Reagan's invitation, issued earlier in the afternoon, the other four candidates had also shown up at the high school and were waiting in a holding room. At one point, the four of them conferred with Reagan's national political director, Charles Black. Black was dispatched to ask Bush's campaign manager, James A. Baker, if Bush would meet with Reagan and the other candidates. Campaign manager Baker rejected the request, according to all parties concerned.

The Reagan aide returned to the candidates and it was decided that Sen. Gordon J. Humphrey (R-N.H.) would be dispatched to ask Bush directly to meet with the candidates in order to discuss broadening the debate. dAccording to Bush's campaign manager Jim Baker, Bush rejected the meeting. And when Humphrey pressed him about what would be good for the Republican Party, Bush, former chairman of the Republican National Committee, told Humphrey, according to James Baker, "Don't you lecture me about the GOP. I've worked a lot harder than you have to build the Republican Party."

James Baker said Bush would not meet with the other candidates to discuss broadening the debate because "we wanted to stick with the letter of the [arrangements originally made] by the Nashua Telegraph. It wasn't our call -- it was the Telegraph's call."

To meet with the other candidates would have been "unwise," James Baker said, adding:" "It was five against one . . . We have not been reluctant to debate but they gang up on you. They cut a backroom deal. It's let's stop George Bush."

And in the band room, as the debate played on, the excluded candidates were in the midst of doing just that. "Clearly the responsibility for this travesty is on Mr. Bush," said Anderson. He charged that Bush had shown "arrogance before the first primary in the nation has even started."

Then there was Howard Baker, angrier than many reporters have seen him in the past. "This is the most flagrant effort" to stifle debate, he said. "It is an effort to reinstitute closed door politics . . . If he is the front-runner, he wears the crown most unbecomingly."

Crane charged that the whole event was a fraud.

And Dole said: "George Bush torpeodoed us tonight . . . As far as George Bush is concerned, he had better find himself another party," As he walked off the stage after being excluded from the debate he told Bush: "There will be another day, George."

The four men said they would work to deprive Bush of the GOP nomination, but they stopped short of saying that they would join in any organized effort to stop Bush or jointly back any other candidates. Howard Baker summarized their views when he said, "If George Bush is the nominee, I will support him, but I will do everything I can to see that does not happen."

Bush, cornered by the press after the debate insisted that all he was doing was "keeping my word." He said that he had heard earlier that Reagan had wanted to cancel. Asked why, he said, "I don't know why. The newspaper told me he wanted to cancel. I don't know why I don't go into these details. I keep my word."

Down the corridor and around the corner from the bandroom where the also-rans were lambasting Bush, leaning against a wall outside the gymnasium where Reagan was debating Bush, Reagan campaign manager John Sears was leaning against the lockers. He was smiling. Reagan aide Charles Black came up and shook Sears' hand. "Another day on the campaign trail." Sears said, smiling at the end of what he obviously felt had been a day well spent.