TAMPA, Fla. -- Mitt Romney on Thursday kicked off the final phase of his bid to become the 45th president, accepting the Republican nomination and urging the country to look closely at his résumé, his vision and his remedies for the ailing economy."I wish President Obama had succeeded, because I want America to succeed. But his promises gave way to disappointment and division," Romney told a raucous crowd waving signs saying "Believe" and "Mitt!""This isn't something we have to accept," he insisted. "Now is the moment when we can do something. And with your help we will do something."Romney's 38-minute speech was the final act of a tightly scripted Republican National Convention that briefly went off course just as the candidate was due to speak.Actor-director Clint Eastwood introduced Romney with a rambling speech that included a debate with an empty chair. Sen. Marco Rubio of Florida followed and quickly got the proceedings back on a loftier track."Do we want our children to inherit our hopes and dreams, or do we want them to inherit our problems?" he asked. "Mitt Romney believes that if we succeed in changing the direction of our country, our children and grandchildren will be the most prosperous generation ever and their achievements will astonish the world."Then came Romney, walking through the crowd, grasping the hands of delegates, slowly coming down the red carpet in a move that put him in close contact with smiling delegates, a visual rebuttal to his image as aloof and out of touch.He jogged up the stairs to the lectern, waved gently to the crowd and stood with a polite smile as delegates bounced and cheered in front of him."Mr. Chairman, delegates, I accept your nomination for president of the United States."After the cheers subsided, thousands at the Tampa Bay Times Forum, and up to 40 million people across America, prepared to take the measure of the man Republicans hope can topple President Barack Obama.Romney appealed to the nation's enduring optimism. "Now is the moment when we can stand up and say, 'I'm an American. I make my destiny. We deserve better. My children deserve better. My family deserves better. My country deserves better,'" he said, his voice rising. "So here we stand. Americans have a choice, a decision."Romney got one of his biggest cheers when he said Obama "promised to begin to slow the rise of the oceans ... and heal the planet. My promise ... is to help you and your family."Romney said he understands that many are disappointed with Obama, whose job approval numbers in some polls have been under 50 percent."Hope and change had a powerful appeal," Romney said, recalling Obama's 2008 mantra. "But tonight I'd ask a simple question: If you felt that excitement when you voted for Barack Obama, shouldn't you feel that way now that he's President Obama?"You know there's something wrong with the kind of job he's done as president when the best feeling you had was the day you voted for him," said the 65-year-old former Massachusetts governor and business executive.The speech was Romney's first and best chance to stand before the nation alone as his party's nominee, his message unfiltered, and make his case. He focused heavily on the economy."I am running for president to help create a better future," Romney said. "A future where everyone who wants a job can find one. Where no senior fears for the security of their retirement. An America where every parent knows that their child will get an education that leads them to a good job and a bright horizon."Romney said: "What America needs is jobs. Lots of jobs. In the richest country in the history of the world, this Obama economy has crushed the middle class."Family and religionRomney faces two perceptions that have dogged him throughout his presidential run: That he lacks warmth and that his positions on issues are too malleable.He spoke of his family, occasionally choking up."My mom and dad gave their kids the greatest gift of all, the gift of unconditional love. They cared deeply about who we would be, and much less about what we would do," Romney said.His parents were well-known political figures in his native Michigan. His father, George, was the governor from 1963 to 1969, and his mother, Lenore, ran unsuccessfully for a U.S. Senate seat in 1970. Mitt Romney talked about his wife, Ann, who addressed the convention Tuesday night and received praise for her speech.With his faith still causing quiet resistance among evangelical Christians -- he would be the first Mormon president -- Romney patiently described what his faith meant to him as his family moved to new places."We were Mormons and growing up in Michigan, that might have seemed unusual or out of place. But I really don't remember it that way," he said. "My friends cared more about what sports teams we followed than what church we went to."