Republicans launched a sharp assault on President Barack Obama's economic record on the first full day of their convention on Tuesday and praised Mitt Romney as a leader who could rein in big government and kick-start a stagnant economy.
After a storm threat delayed the convention one day, Republicans formally nominated Romney and his running mate, Paul Ryan, to challenge Obama for the White House in a November 6 election that polls show is tight.
Republicans repeatedly accused Obama of being hostile to small business owners, burying them under high taxes and excessive regulations that stunted job growth. His signature healthcare overhaul, they said, was big government run amok.
"It's time to end this era of absentee leadership in the Oval Office and send real leaders to the White House. America needs Mitt Romney and Paul Ryan and we need them right now," said Chris Christie, the combative New Jersey governor who delivered the convention's keynote address.
"Mitt Romney will tell us the hard truths we need to hear to put us back on the path to growth and create good-paying private sector jobs again in America," he said.
Republicans are using the convention to make the case for booting Obama from office while presenting a softer side of Romney, who has struggled to overcome a "likability gap" with the president and refute critics who paint him as a job-killing, out-of-touch former private equity executive.
Obama, campaigning in Iowa and Colorado, dismissed the Republican attacks and told students at Iowa State University that the agenda his political foes were rolling out in Tampa made for a "pretty entertaining show."
He also accused Republicans of stretching the truth in a multi-million-dollar ad effort to get him out of the White House.
"They'll just make stuff up if they have to. They're doing it already," he said at an event in Fort Collins, Colorado. "Sometimes -- how do I put this nicely? -- they will just fib."
Polls show Romney trails Obama badly with women, and the convention featured a series of women speakers capped by Romney's wife, Ann. She said her husband had attacked every challenge - from reviving the struggling Salt Lake City Olympics to helping her battle multiple sclerosis and breast cancer.
"At every turn in his life, this man I met at a high school dance has helped lift up others," Ann Romney told the convention. At one point she shouted to fans: "I love you, women."
"This is the man who will wake up every day with the determination to solve the problems that others say can't be solved, to fix what others say is beyond repair," she said in a speech timed to air during the one hour of prime-time coverage by U.S. television networks.
The former Massachusetts governor, who flew to Tampa earlier in the day, came onstage and gave his wife a kiss after her speech, getting a rousing reception from delegates.
But even as Republicans tried to show a united front against Obama, it was clear the bitter party divisions evident in the long and bruising presidential primary battle have not been resolved.
Supporters of libertarian congressman Ron Paul of Texas and other conservative activists briefly disrupted the opening session, booing a decision to unseat Paul delegates from Maine and institute rules changes they believe will weaken their power in the next election cycle.
The rules changes, approved by the convention on a voice vote, will bind delegates to the results of a statewide vote and reduce the role of smaller state-level conventions where Paul had success.
Opponents of the move said Romney's operatives and the party's establishment were trying to freeze them out. Some noted that during the state-by-state roll call of delegates to count votes for the nomination, only Romney's vote totals were announced from the podium.
"We were disenfranchised by our party. We won't participate with this chaos," said Russell Montgomery, 52, of St. George, Maine. "We won't legitimize this fiasco. This is as bad as the other party - the corruption."
Former U.S. Senator Rick Santorum, Romney's chief rival in the primaries and a favorite of social conservatives who have had trouble warming to the former Massachusetts governor, addressed the convention but mentioned Romney by name only three times.
"Under President Obama, the dream of freedom and opportunity has become a nightmare of dependency with almost half of America receiving some government benefit," Santorum said.
Republicans painted Obama as a force for expanding government and said his policies had failed to bring down high unemployment or control budget deficits and federal debt.
The theme for the night, "We Built It," was a reference to Obama's "you didn't build that" comment in July that Republicans have used as an attack line against him. The comment referred to the government help that business owners receive.
"We can do better. We can do a lot better. It starts with throwing out the politician who doesn't get it, and electing a new president who does," House of Representatives Speaker John Boehner said.
Republicans hope the convention will not be overshadowed by Hurricane Isaac, which hit the Louisiana coast not far from New Orleans on Tuesday night, just before the seventh anniversary of Hurricane Katrina's deadly strike on the city. They also worry about being seen celebrating Romney's nomination while swathes of the Gulf Coast are under storm threat.
While Tampa was spared the brunt of Isaac, a destructive landfall in Louisiana could create uncomfortable split-screen television images of the convention juxtaposed with the hurricane.
The Republicans used the first night to highlight some of their rising stars. Christie's speech was highly anticipated, offering plenty of lessons he learned as a Republican governor in Democratic New Jersey who has become known for his in-your-face style.
"I know this simple truth and I'm not afraid to say it: our ideas are right for America and their ideas have failed America," Christie said. "We win when we make it about what needs to be done; we lose when we play along with their game of scaring and dividing."
Artur Davis, a black former Democratic congressman from Alabama who switched to a Republican, said he had been fooled by Obama's promises in 2008.
"But dreams meet daybreak: the jobless know what I mean, so do the families who wonder how this administration could wreck a recovery for three years and counting," Davis said.
The Republican gathering culminates with Romney's nationally televised acceptance speech on Thursday, the biggest speaking engagement of his political life. Vice presidential contender Ryan, a Wisconsin congressman, tops the bill of speakers on Wednesday.