"Can we do better?" U.S. House Speaker and Convention Permanent Chairman John Boehner asked the delegates. "The answer, in my view is obvious -- you bet we can."
The first day of the convention at the Tampa Bay Times Forum saw Mitt Romney officially nominated as the party's presidential candidate and Rep. Paul Ryan of Wisconsin nominated as the party's vice presidential candidate.
Boehner, of Ohio, said Obama has been offering excuses, not answers, for the poor economy, stagnant job market and the housing crisis.
"He has the nerve to say he's moving us forward and the audacity of hope that we believe him," Boehner said playing on the title of Obama's book, "The Audacity of Hope."
"We can do better," Boehner said. "We can do a lot better."
Romney comes from a family of builders and Republicans are in Tampa to "preserve this country in the same way we built it," Boehner said. "President Romney -- boy, I like the sound of that -- will keep his word and keep his courage, too."
But to get elected Romney and Ryan "need all of you in all the way all of the time" until Nov. 6, Boehner said.
Building on the "We built it" and "We can do better" themes, RNC Chairman Reince Priebus said, "Tonight we embark on a better future for every American. Mitt Romney and Paul Ryan will lead us, and our timeless, tested Republican principles will light the way."
Priebus said the 2012 election is a "rendezvous with destiny."
"We can't afford any more disappointments," Priebus said. "We need a new direction. We need a new president. I know, and you know, just the man for the job. ... The president America needs is Mitt Romney."