The decision by a former speaker of the House, Newt Gingrich, to forgo the 2008 presidential race will diminish the quality of the debate about the direction the Republican Party needs to go. The absence of one of the country’s most inventive conservative thinkers and astute tacticians, however, also serves notice to the Republican candidates that if he has concluded that he cannot win, they have set themselves a formidable task.

Mr. Gingrich yesterday blamed his inability to proceed on ostensibly unforeseen implications in the McCain-Feingold campaign finance law, but it seems more likely that the architect of the radical conservative 1989 “Contract with America” believes he would not win the nomination and could not win the general election.

Mr. Gingrich told Chris Wallace of “Fox News Sunday” yesterday that what he called “the McCain-Feingold censorship act” meant he would not legally be able to continue taking funds from the think tank he founded, American Solutions, which is registered as a 527 fund-raising group. “I wasn’t prepared to abandon American Solutions even to explore whether or not a campaign was realistic,” he said. It seems unlikely, however, that Mr. Gingrich could have remained ignorant for so long about the implications of the campaign finance law. He had floated the idea of a presidential run since the beginning of the year; it appears that insufficient financial backers emerged to allow Mr. Gingrich to mount a winning campaign.

“We had several million dollars in pledges and would clearly have been competitive financially within three weeks,” he told George Stephanopoulos on ABC’s “This Week,” before saying, “It would have been an underdog campaign.”

Although Mr. Gingrich’s suggestion that the campaign finance law amounted to an attack upon free speech was a sideswipe at legislation’s co-author, Senator McCain, the former speaker was not prepared to throw his weight behind any of the other Republican candidates. Instead, he urged them to take into account the electorate’s intense dislike of how Washington operates.

“Republicans have to find a way to represent a future that is different, without getting in a fight with Mr. Bush, and it is a very difficult balance,” Mr. Gingrich said. Both the front-runner for the Republican nomination, Mayor Giuliani, and one of his closest challengers, Mitt Romney, are distancing themselves from President Bush, he said, citing the Katrina disaster in New Orleans, the failure to secure the border with Mexico, and what he called “bureaucracies” as reasons that Washington is unpopular. And he offered praise to outsider Mike Huckabee, who he said appears to be a genuine Beltway outsider. The former governor of Arkansas is “very attractive and, if he can find the money, competitive overnight.” “You just have to like him,” he said.

However, Mr. Gingrich’s decision not to enter the race was taken in the context of his long-held belief that the Democratic front-runner, Senator Clinton, is “the most likely winner but not a landslide winner” in 2008 and that she stood “an 80% chance she would be president.”

He said he could not think of a way other Democratic candidates could catch her. “I don’t know how they take her on without going to the left. And if they go to the left, they position her as a centrist,” he said.

His advice to whoever ultimately emerges as the Republican candidate is to ignore personal attacks on Mrs. Clinton and instead stress that Democratic policies are out of sync with what Americans believe.

There is little use in trying to use Swiftboat tactics to tarnish her, he said. “I think trying to beat Senator Clinton personally is insane. Everyone who is going to vote against her already knows everything,” he said. The question Republicans must ask voters is, “Does America want to go where she is going to take America?”