TAMPA, Fla. -

With a rowdy fist-pump, blunt and brash New Jersey Gov. Chris Christie lit a fire under the Republican National Convention, labeling Democratic President Barack Obama part of the complacent status quo.

"It's been easy for our leaders to say not us, and not now, in taking on the tough issues. And we've stood silently by and let them get away with it," the first-term Republican governor said with a rock star's rasp during the keynote address Tuesday night. "But tonight, I say enough."

His mission was to make the case against Obama and fire up a convention delayed in its start by a tropical storm.

Like a coach before a football game, Christie implored the thousands inside the Tampa Bay Times Forum to rally behind GOP nominee Mitt Romney and his running mate, Paul Ryan.

"Everybody stand up. There's no time left to waste," the outspoken former prosecutor shouted.

"What will our children and grandchildren say of us? Will they say we buried our heads in the sand, we assuaged ourselves with the creature comforts we've acquired, that our problems were too big and we were too small, that someone else should make a difference because we can't?" he told his fellow Republicans. "Or will they say we stood up and made the tough choices needed to preserve our way of life?

Judging by the thundering cheers inside the arena, Christie hit his mark. That outspoken style made him a Republican Party star and helped earn him the plum, prime-time speaking gig.

He rocketed up the GOP ranks in 2009, winning the Democratic-heavy Eastern state the year after Obama was elected and establishing a reputation as confrontational to big labor and public employees. Early in the GOP nominating campaign, Republicans uninspired by Romney aggressively urged Christie to seek the nomination.

New York delegate David Shimkin said he admired Christie's frankness. "He doesn't seem to have a filter. A lot of candidates don't do that," Shimkin said.

As keynote speaker, Christie was tasked with making the prime-time pitch for Romney, who remains something of a mystery to voters even though polls show him locked in a close contest with Obama.

Christie considered running for the nomination himself but months ago decided to endorse Romney, who made a personal entreaty for Christie's support as the GOP primaries were getting under way.

Christie on Tuesday waved off a published report that he had turned down an offer to be Romney's running mate because he didn't think Romney could win in November.

"Not only do I believe he can win, I think he will win," Christie told "CBS This Morning."

Temperamentally and stylistically the opposite of the buttoned-up Romney, Christie acknowledged in interviews that the former Massachusetts governor has work to do to close the sale with some voters, especially women.

"Mitt Romney's going to have to win this campaign. He's going to have to let the American people see who he is," Christie said on ABC's "Good Morning America," adding that Romney's choice Ryan as his running mate had brought more energy to the ticket.

After he toppled Democratic Gov. Jon Corzine in 2009, national Republicans embraced Christie for his tough talk on fiscal matters and for taking on public employee unions, especially teachers. Web videos of Christie berating teachers at town hall meetings quickly went viral, giving Christie a large national audience. Critics dubbed him "Gov. YouTube," suggesting he was more interested in getting publicity for himself than for improving New Jersey's finances.

Democrats warned that viewers shouldn't buy Christie's claim of a "Jersey comeback." They pointed to economic data showing the state still grappling with weak employment and high property taxes.

"Chris Christie is taking the stage in Tampa tonight to talk about his favorite topic: himself," state Assemblyman John Wisniewski told reporters during a conference call before the speech. "Gov. Christie's record in New Jersey is certainly not a model for our nation, and the people in Tampa should know that."

Maryland Gov. Martin O'Malley, chairman of the Democratic Governors Association and a likely 2016 presidential contender, went further, saying he expected Christie to deliver an "angry, Don Rickles keynote extolling the virtues of their candidate, Mitt Romney, who had one of the worst job creation rates in the nation."