President Obama planned to tell voters in his nomination speech Thursday night that he needs “more than a few years” to tackle the country’s challenges, claiming he’s still going through an inbox that had “built up over decades.”

In prepared remarks released ahead of the president’s convention address, Obama says, as he has before, that this election is about “two fundamentally different visions for the future.” He describes his plan as a tougher one, but one that leads to better results.

“I won’t pretend the path I’m offering is quick or easy. I never have. You didn’t elect me to tell you what you wanted to hear. You elected me to tell you the truth. And the truth is, it will take more than a few years for us to solve challenges that have built up over decades,” Obama is expected to say.

“But know this, America: Our problems can be solved. Our challenges can be met. The path we offer may be harder, but it leads to a better place.”

Earlier in the day, Obama campaign officials suggested the president’s critical address would drop some of the lofty rhetoric from 2008 and aim more to spell out a plan for the country.

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"Tonight is not about magic. It's about being pragmatic. It's about the future," an Obama official told Fox News. "It's not about the rhetoric, it's about the vision."

Obama will offer "some new ideas" when he discusses his practical plan for economic growth, campaign officials said, and will also address other issues like education and clean energy.

A bullet-point outline released by the campaign said the president is setting goals to “double exports by the end of 2014,” “cut net oil imports in half by 2020” and “reduce the deficit by more than $4 trillion over the next decade.”

The speech excepts show Obama invoking President Franklin Roosevelt and the New Deal.

“It will require common effort, shared responsibility, and the kind of bold, persistent experimentation that Franklin Roosevelt pursued during the only crisis worse than this one," Obama says. "And by the way – those of us who carry on his party’s legacy should remember that not every problem can be remedied with another government program or dictate from Washington.”

Mitt Romney, in a brief statement ahead of the address, challenged Obama to give a progress report on the many promises he made in 2008.

“What I’d like him to do is report on his promises, but there are forgotten promises and forgotten people,” Romney said. “Over the last four years, the president has said that he was going to create jobs for the American people and that hasn’t happened. He said he would cut the deficit in half and that hasn’t happened. He said that incomes would rise and instead incomes have gone down.

"And I think this is a time not for him not to start restating new promises, but to report on the promises he made. I think he wants a promises reset. We want a report on the promises he made.”

The stage for the Democratic nomination address has been scaled down due to weather, with the campaign announcing a day earlier that the threat of rain and lightning would force the address to be moved from the 72,000-seat Bank of America Stadium to the much smaller, and enclosed, Time Warner Cable Arena.

Obama's speech is designed not to persuade delegates, but to reach the family sitting behind a TV set in Des Moines and all over the country, the campaign said.

But the question remains as to whether this president, among the most celebrated orators of his generation, can still summon the powers of persuasion that helped get him elected in the first place.

His advisers think so. Senior adviser Robert Gibbs said: "You're not seeing him for the first time or the 10th time. But I think he will meet the moment."

Aides tried to contrast what Obama's about to do with what Romney did in his nomination acceptance speech last week in Tampa. They said the GOP candidate offered "no idea" about what the future would be like under a Romney presidency.

Romney, though, posed what would be a troubling question for the Obama campaign when he asked in Tampa whether the country is better off than it was four years ago. Romney claimed it was not, and Obama aides initially hesitated on the question before top surrogates argued this week that the country is, in fact, better off.

Campaign officials said Vice President Biden, who speaks before the president Thursday, will serve as Obama's "character witness," discussing tough decisions the commander-in-chief has made -- most notably, Obama's order to take down Usama bin Laden, campaign officials say.

Former President Bill Clinton fired up the Democratic base Wednesday night in a speech that defended Obama's record, while also hitting Romney and running mate Paul Ryan for their attacks on Obama's economic record.

"No president -- not me or any of my predecessors -- could have repaired all the damage in just four years. But conditions are improving, and if you'll renew the president's contract you will feel it," he said.

"Last night was about his record," an Obama official said. "Tonight is about the future."

Fox News' James Rosen contributed to this report.