Fred Thompson officially entered a wide-open Republican presidential race Thursday, vowing to invigorate a dispirited GOP and promising to thwart another Clinton from capturing the presidency.

The actor and former Tennessee senator harkened to the GOP glory days of 1994 when he and other Republicans seized control of Congress and established an equal counterpoint to Democrat Bill Clinton in the White House. Now an official candidate for the Republican nomination, Thompson promised to return the party to better times.

“In 1992, we were down after a Clinton victory,” Thompson said in a 15-minute webcast that laid out the rationale for the candidacy he also declared on “The Tonight Show” with Jay Leno.

“In 1994, our conservative principles led us to a comeback and majority control of the Congress. Now, you don’t want to have to come back from another Clinton victory. Our country needs us to win next year, and I am ready to lead that effort,” he said.

Thompson also swiped at his leading Republican rivals, Rudy Giuliani and Mitt Romney, without naming them, saying: “In 1994, when I first ran, I advocated the same commonsense conservative positions that I hold today.”

Thirteen years ago, Giuliani was a New York mayor who espoused liberal-to-moderate positions on social issues and endorsed Democratic Gov. Mario Cuomo. Romney was a moderate challenging Sen. Edward M. Kennedy in liberal Massachusetts.

Today, some conservatives question Giuliani’s and Romney’s credentials – and Thompson sees an opening for his candidacy.

Wednesday night, Giuliani, Romney and six other GOP hopefuls participated in a debate in Durham, N.H., on the campus of the University of New Hampshire.

All eight men on stage welcomed Thompson to the race with barbed humor and pointed advice.

“This is a nomination you have to earn,” said former New York Mayor Rudy Giuliani. “Nobody’s going to give it to you. Nobody’s going to grant it to you.”

“I was scheduled to be on Jay Leno tonight, but I gave up my spot to somebody else because I’d rather be here in New Hampshire,” joked former Arkansas Gov. Mike Huckabee.

On other topics, the presidential contenders voiced support for the Iraq war despite a warning from anti-war candidate Ron Paul that they risk dragging the party down to defeat in 2008.

“Even if we lose elections, we should not lose our honor,” shot back Huckabee, “and that is more important to the Republican Party.”

Sen. Sam Brownback of Kansas and Rep. Duncan Hunter of California called for the resignation of Sen. Larry Craig, the Idaho Republican who pleaded guilty to disorderly conduct in an airport men’s room in an undercover police operation.

Brownback drew boos from the audience when he called for passage of a constitutional amendment to ban gay marriage. “I understand there is a divided audience,” he said.