Mitt Romney officially clinched the GOP presidential nomination on Tuesday to move a step closer in his five-year quest for the White House.

To roaring cheers at the Republican National Convention in the packed Tampa Bay Times Forum, the delegation from New Jersey put Romney above the 1,144-delegate threshold, ensuring he will be the GOP challenger to President Barack Obama in November.

Earlier, the 2,200-plus convention delegates approved a conservative platform that called for less government, opposed same-sex marriage and endorsed a "human life amendment" to ban abortion with no specific exceptions for cases of rape, incest or when the mother's life is threatened.

Romney and his running mate, Rep. Paul Ryan of Wisconsin, will be formally nominated on Thursday, and Romney's acceptance speech that night will conclude the convention that had its agenda delayed by Hurricane Isaac, which hit Louisiana as early evening speakers addressed the delegates.

Republican officials appeared determined to stick to a tightened three-day schedule that kicked into full gear earlier in the day with official business and speeches accusing Obama of failed leadership and undermining the American dream.

Speaker after speaker emphasized their own humble beginnings as descendants of immigrants who worked hard to achieve success for their families and never expected government help or handouts.

Romney's wife, Ann, repeatedly referred to her first date with the man she fell in love with in urging Americans to trust him to fix the nation's problems. In the biggest political speech of her life, Mrs. Romney touched on issues considered vulnerabilities for her husband -- support from women, his personal wealth -- and encouraged people to look closely at his record and get to know him for the warm and loving man she met at that high school dance.

"You are the best of America," Mrs. Romney said of the nation's women. "You are the hope of America. There would not be an America without you. Tonight we salute you and sing your praises."

She avoided any mention of controversial issues such as the anti-abortion stand in the convention platform that polls show is opposed by most Americans, instead focusing on the day-to-day challenges facing women throughout the country.

"I'm not sure men really understand this, but I don't think there's a woman in America who really expects life to be easy," she said. "We're too smart to know there aren't easy answers but we're not dumb enough to expect there aren't better answers."

She concluded by declaring "you can trust Mitt," adding: "He loves America. He will take us to a better place, just as he took me home safely from that dance."

As the convention crowd cheered and applauded, Romney came out in his first appearance at the convention to hug and kiss his wife, telling her: "You were fabulous."

Earlier, Republican National Committee Chairman Reince Priebus launched the litany of attacks on Obama, saying that another term for the president and Vice President Joe Biden will mean "four more years of failure."

In reference to Obama, Priebus said "he hasn't even run a garage sale or seen the inside of a lemonade stand." The nation needs a president "with real experience in a real economy," Priebus added. "Mitt Romney will be that president."

Other speakers continued the effort by Priebus to frame the election as a referendum on Obama's policies.

"The American people are still asking 'where are the jobs,' but President Obama only offers excuses instead of answers," U.S. House Speaker John Boehner told the delegates. "His record is a shadow of his rhetoric. Yet he has the nerve to say that he's moving us forward, and the audacity to hope that we'll believe him."

Boehner also said "we can do better," adding that "it starts with throwing out the politician who doesn't get it, and electing a new president who does."

Rep. Dan Benishek of Michigan complained earlier that Democrats in Washington were "spending away our children's and grandchildren's futures," while Rep. Tim Scott of South Carolina serenaded Obama with a chorus of the Ray Charles tune, "Hit the Road, Jack."

At a campaign event in Iowa, Obama said Tuesday that he expected the GOP convention to be "a pretty entertaining show."

"I am sure they will have some wonderful things to say about me," the president said. "But what you won't hear from them is a path forward that meets the challenges of our time."

New Jersey Gov. Chris Christie concluded the first night of speeches with a keynote address that declared Republicans were willing to face the tough issues and find solutions that work, instead of taking the easy way out and pandering for voter support.

"Leadership delivers. Leadership counts, and leadership matters," Christie said, recounting his own record of reforms as a GOP governor in a majority Democratic state.

"Mitt Romney will tell us the truths we need to hear" and solve the problems worsened by an "era of absentee leadership in the White House," he added.

In a sign of lingering internal division in the party after a rugged primary campaign won by Romney, rival candidate Rep. Ron Paul of Texas was thronged by supporters when he entered the convention floor before Tuesday's session convened. Some Paul supporters shouted "let him speak," referring to their candidate's exclusion from the convention agenda.

Paul supporters later protested a rule change adopted by the convention that they believe will hinder their kind of grassroots campaign in the future. They also cheered wildly when Paul received any delegates in the state-by-state roll call.