The torch was being passed, and Gerald Ford had to sense it as he stood beaming before a Republican convention that was giving its party leader a last hurrah.

That ovation Monday night, some of those closest to him now feel, was the moment when the former president felt his first flicker of second thoughts.

"The guy has never really had the fire in the belly," said one of his closest advisers. ". . . But I just don't think he was ready to surrender the torch."

And so a dramatic and unexpected new chapter was begun in the saga of this former president who has become a current political paradox. Before it was over, Gerald Ford would treat the Grand Old Party, and the rest of the nation, to one of the more theatric and climactic moments in political conventioneering.

Gerald Ford, America's only appointed president, never wanted the 1980 presidential nomination badly enough to do it right. He would not set about the stumping and speechmaking and planning last fall that could have taken him to a rematch with Jimmy Carter this year. But in the spring -- when it was too late -- he felt those twinges of doubt and tickles of ambition. Ford tried to create his own presidential draft, only to discover, much to his political embarrassment, that he could not even whip up a conventional breeze.

So instead, Ford came to the Republican convention prepared to address it for the last time as the man who had last been the party standard bearer. But he was not prepared, perhaps, for the personal and political significance of the performance.

"Until he spoke to the convention, I just don't think that he ever had come to grips with the fact that the speech meant that his political career was over," says one of those who would later be in the group that used the prospect of a comeback as a lever in trying to persuade Ford to try once again, this time as Ronald Reagan's vice president with new-and-improved power.

The portrait of the former president moving toward his onetime foe's vice presidency, as revealed in interviews with a number of the principals involved, is a picture of a man wrestling the conflicting forces of pride, responsibility and ambition . . . a man keeping a hectic schedule with little sleep . . . who allows himself to be nudged and finally budged by advisers whose motives ranged from patriotic duty to party loyalty to personal career gains.

It is a portrait of a man vacillating under intense pressure brought on, in part, by those advisers who were closest to him. For weeks he had been saying a firm no. But this week he ginergly gave his advisers permission to explore with Reagan aides the prospect of structuring a vice presidency for a former president.

Then, on Wednesday afternoon, he slipped back into a strong negative posture. "I've given most of my life to this country," Ford said during a meeting with his confidants, his voice rising in emotion and intensity. I've done the whole sled run. I've given. I'll campaign for the ticket in the fall. But don't ask me to do this."

Yet just a couple of hours later, at 7:15 p.m., there was Ford sitting in the booth with Walter Cronkite, talking more positively about the proposal in public than his Detroit confidants had ever heard him in private. He had started the interview cautiously, voicing what sounded like conceptual rejection, but the more he talked, the more the prospect seemed to excite him until live and in color, he exhibited unmistakable flashes of ambition and inclination to give it one more try.

"If there is to be any change," Ford said, "it has to be predicated on the arrangements that I would expect as a vice president in a relationship with a president . . . If I go to Washington, and I am not saying that I am accepting, I have to go there with the basic belief that I will play a meaningful role across the board in the basic and the crucial and the important decisions that have to be made in a four-year period . . . Before I can even consider any revision in the firm position I have taken, I have to have responsible assurances."

And when Cronkite called the concept "something like a co-presidency," Ford did not dissuade him of the notion. He embraced it on his own. "That's something that Gov. Reagan really ought to consider," Ford said. ". . . the point you raised is a very legitimate one."

Ford's comment astounded some of those who had been closest to him in the past 24 hours. And it astounded Republicans of some prominence elsewhere in Detroit as well.

On the 69th floor of the Detroit Plaza Hotel, Ronald Reagan leaned forward in his chair, peering intently at the television screen across the room. His lips drew down into a taut line and he shook his head from side to side in obvious displeasure.

On the 19th floor of the Pontchartrain Hotel, George bush had a sinking feeling as he heard what seemed to be a clear indication that Ford was moving toward forging a deal that would make him a co-president and would make Bush unemployed. And Bush's speechwriter, the redoubtable Vic Gold, a former press secretary to Spiro Agnew, exploded in archetypical anger, "Pride? What does he know about pride, that horse's ass!"

Ford would later deny that a "co-presidency" had ever been discussed in his talks with Reagan or the talks between his advisers and Reagan's. What had been discussed, others involved say, was making Ford a sort of "executive vice president" or a "deputy president."

But the fact that Ford embraced the term "co-presidency" on nationwide television, at this most sensitive moment in the negotiations, had already done damage. It had, for example, reportedly angered Reagan by seeming to diminish his image of being able to handle the job single-handed.

And it surprised those who thought they knew Ford best. "The whole concept of a co-presidency shows a lack of sophistication about the office," one of those advisers said in dismay. "And I hate to say it, but that's a helluva thing to say about a man who has held the office."

In the end, the former president, whose suite was on the 70th floor of the Detroit Plaza, had wound up traveling to the convention hall booth of Walter Cronkite to send a message to Reagan, who was in his own suite on the 69th.

He really had not meant to put public pressure on Reagan to agree to his concessions, nor to embarrass him by embracing the notion of a co-presidency, Ford's advisers maintained. They said he went on television then simply because he had been scheduled weeks ago. So too, after being up until 3 a.m. the night before, he had awakened at 6 a.m. to do the Today Show, and then held a series of on-the-record interviews throughout this day of decision.

Ford's use of the Cronkite channel of communication to make private talks public -- and his willingness, if not eagerness, to try to restructure the vice presidency in his image -- was "truly regrettable," in the words of one prominent Republican who advised him this week.

He attributed the move not to strategy, but fatigue. "I really think he was very tired and very pressured," he said. "It's unfair to him to go into something this enormous and complex in this short period of time. He was just too tired to think it all out clearly."