DAVENPORT, Iowa – A confident Mitt Romney returned to Iowa on Tuesday evening to deliver a formal speech kicking off his aggressive campaign sprint heading into next Tuesday’s Republican caucuses.

On a day when his Republican opponents questioned Romney’s avowed conservatism, Romney made no mention of his intraparty rivals in his speech here and sounded instead a message fit for the general election.

Speaking in the ornate ballroom of the Hotel Blackhawk in downtown Davenport, down the street from where President Obama campaigned four years ago almost to the day, Romney sought to sharpen the contrast between himself and the incumbent. Romney accused Obama of not fulfilling his campaign promises to unite the nation and end Washington’s gridlock.

“He closed with these words: ‘This is our moment, this is our time,’” Romney said, quoting from Obama’s 2008 Davenport speech. “Well, Mr. President, you have now had your moment. We have seen the results. And now, Mr. President, it is our time.”

“Where you once challenged us to reach for our dreams, you now ask us to settle for less,” Romney said, running through a litany of poor economic statistics he blamed squarely on the president. “Once, Barack Obama appealed to our better angels; today, he demonizes fellow Americans.”

Obama campaign spokesman Ben LaBolt accused Romney of backing economic policies that would let Wall Street “write its own rules again” and that hurt the middle class.

“While President Obama is fighting for an economy that rewards hard work and responsibility and provides every American with a fair shake, Mitt Romney believes in skewing the playing field toward those at the top while leaving Americans facing a challenge on their own,” LaBolt said in a statement.

Romney attracted one of the biggest and most enthusiastic crowds of his campaign yet, with about 300 people crammed into the ballroom and a few hundred more outside. Looking out at the crowd with his wife, Ann, Romney exclaimed from the stage: “The hallways are full, the stairways are full, this is just amazing. I don’t know how you got here, but I appreciate it.”

The audience repeatedly interrupted Romney’s speech with hearty applause, and the candidate stayed for more than 15 minutes after to shake hands and sign autographs.

In the 15-minute address, Romney presented his closing argument and cast the election as “a choice between two destinies.”

“I am tired of a president who wakes up every day, looks across America and is proud to announce, ‘It could be worse,’” Romney said. “It could be worse? Is that what it means to be an American? It could be worse? Of course not. What defines us as Americans is our unwavering conviction that we know that it can be better.”

Romney charged that Obama had directed “paybacks and boondoggles” to “friends in the green-energy business,” like the Solyndra solar-panel company. He said entrepreneurs and businesspeople “feel under attack by this administration.” Romney pledged to repeal Obama’s health-care law and a slew of federal regulations that he said inhibit business growth.

Romney closed with a direct pitch to Iowa Republicans: “If you believe the disappointments of the past few years are a detour, not our destiny, then I am asking for your vote.”