TAMPA, Fla. — Former Massachusetts Gov. Mitt Romney swept to the Republican presidential nomination Tuesday night, praised lovingly by his wife from the stage as the “man American needs” and cheered by a hall packed with convention delegates eager to propel him into the fall campaign against President Obama.

The hall erupted in cheers when Romney strolled onto the stage and shared a kiss with his wife of more than 40 years.

“This man will not fail. This man will not let us down,” Mrs. Romney said in a prime-time speech that sounded at times like a heart-to-heart talk among women and at times like a testimonial to her husband.

“It’s the moms who always have to work harder, to make everything right,” she said, and she vouched firmly for her husband: “You can trust Mitt. He loves America.”

“I read somewhere that Mitt and I have a ‘storybook marriage.’ Well, in the storybooks I read, there were never long, long, rainy winter afternoons in a house with five boys screaming at once,” she said in her turn at the podium.

“A storybook marriage? No, not at all. What Mitt Romney and I have is a real marriage,” she added, in an appearance meant to cast her multimillionaire-businessman-turned politician husband in a softer, more likable light.

Earlier, the Romneys watched on television at a hotel suite across the street from the convention hall as delegates sealed his hard-won victories in the primaries and caucuses of last winter.

New Jersey put him over the top in a ritual roll call of the states.

New Jersey’s governor, Chris Christie, had the difficult job of following Ann Romney before the cheering crowd.

Christie, the convention keynoter, declared, “Leadership matters.”

“It’s time to end this era of absentee leadership in the Oval Office and send real leaders to the White House,” he said.

Republican mockery of President Obama began almost instantly from the podium at a convention postponed once and dogged still by Hurricane Isaac. The Democratic president has “never run a company. He hasn’t even run a garage sale or seen the inside of a lemonade stand,” declared Reince Priebus, chairman of the Republican Party.

The opening session passed up no opportunity to broaden Romney’s appeal. Speakers included Hispanic candidates for office, former Rep. Artur Davis, a former Democrat and member of the Congressional Black Caucus, businessmen and women and former Sen. Rick Santorum of Pennsylvania, Romney’s most persistent, conservative nemesis in the nominating campaign.

To send Romney and ticketmate Paul Ryan into the fall campaign, the convention quickly approved a conservative platform that calls for tax cuts — not government spending — to stimulate the economy at a time of sluggish growth and 8.3 percent unemployment.

While there was no doubt about Romney’s command over the convention, the residue of a heated campaign for the nomination was evident inside the hall.

Texas Rep. Ron Paul, who never won a primary or caucus, drew several dozen delegate votes. Earlier, his supporters chanted and booed after the convention adopted rules they opposed, but were powerless to block, to prevent those votes from being officially registered.

Opinion polls made the race a close one as the Republicans’ days of pageantry and speechmaking began in earnest, and the man tapped to deliver the keynote address set the stakes.

“Conventions are always huge for a challenger because they’re the ones introducing themselves” to the voters, said Christie.

Convention planners squeezed two days of speeches and other convention business into one after scrapping Monday’s scheduled opener because of fears that Isaac would make a direct hit on the Florida Gulf Coast.

The accelerated plans call for Romney to deliver his formal acceptance speech Thursday night.

Delegates also approved a platform Tuesday, officially taking a stand on a host of issues that have made this election year one of the most divisive in decades. Whatever the impact of those issues, the polls show the economy is overwhelmingly the dominant issue in the race, and on that, the voters narrowly say they trust Romney more.

In an AP-GfK poll taken Aug. 16-20, some 48 percent of registered voters said they trust Romney more on economic issues, to 44 percent for Obama.

However, a Washington Post-ABC News in the days immediately before the convention found that 61 percent of registered voters said Obama was more likable, and 27 percent said Romney.