The Ron-Reagan's campaign organization, badly wanting a head-to-head debate between Reagan and George Bush, today decided to put up the money to sponsor one.

The action rescued the debate, which had faced cancellation earlier in the day after the Federal Election Commission ruled that sponsorship by The Nashua Telegraph would be an illegal corporate contribution by the newspaper to the Bush and Reagan campaigns.

So the Telegraph asked the two candidates to split the $3,500 cost of the debate, most of which is for renting Nashua High School Saturday night and constructing a camera platform.

John Breen, executive editor of the Telegraph, said the Reagan camp readily agreed, but the Bush side balked at putting up the money. Reagan aides then agreed to fund the debate and put the money in escrow to prove it.

The behind-the-scenes behavior of both candidates said far more than the public statements of their campaign managers about the preceived standings in the New Hampshire primary.

The GOP party line is that the race between Bush and Reagan is extremely tight, and that a bland and uninspiring debate among the seven GOP candidates Wednesday night ended in a draw.

Privately, there is a widespread perception that Reagan is fading fast and that Bush would prefer not to risk his front-running status in a one-on-one debate. Knowing that Reagan's refusal to debate in Iowa cost him dearly, Bush has been careful to leave a public impression that he is willing to debate the former California governor any place at any time.

Both camps treated the seven-candidate forum as a warmup for Saturday's 90-minute confrontaton.

"It was promotion for the Saturday debate," said Reagan campaign manager John P. Sears.

"The Saturday debate will be much more adversarial," predicted Bush campaign manager James Baker.

Meanwhile, strategists for Howard H. Baker Jr., indicated that it would be difficult for the Tennessee senator to continue in the race is he does not do well in the New Hampshire primary Tuesday. Doug Bailey, architect of a major Baker television advertising campaign now under way, said that various options are being considered, but that a poor showing here would make fund-raising difficult.

Baker is under some pressure from John B. Anderson, who is exploring the size of the limited market that exists for an avowedly liberal GOP candidate. Anderson, the most spirited candidate in the Wednesday night debate, today picked up the endorsement of the Concord Monitor, the state's third-largest newspaper.

Baker and Anderson campaigned in New Hampshire today. Reagan went to Alabama and Bush to Minnesota after debate performances that didn't delight everyone within their own camps.

Reagan aides were unhappy about the way their candidates fumbled a question on whether Treasury Secretary G. William Miller should resign because of allegations that he should have known, when he headed Textron Corp., that $5 million was being paid in bribes to get business for an overseas subsidiary.

Reagan suggested that bribery was a worldwide way of doing business, and never did answer the question. Later, Reagan said that if he were president he would ask Miller to "retire."

And some Bush aides thought that their candidate had played matters too close to the vest.

"George doesn't take enough chances," said one Bush intimate. "He's just too cautious."