Charlie Riedel, Associated Press
Republican presidential candidate, former Massachusetts Gov. Mitt Romney arrives at a campaign stop at the Music Man Square in Mason City, Iowa Thursday, Dec. 29, 2011.

CEDAR FALLS, Iowa — An optimistic, upbeat Mitt Romney on Thursday accelerated his push in Iowa in the days before the GOP presidential caucuses and defended the relatively little campaigning he has undertaken in the state.

Newly planned events for Iowa showed a confident Romney campaign in the final five days of the state campaign. He had spent months working to lower expectations that he would win here, but the latest polls showed him in a strong position to win outright or finish behind only Texas Rep. Ron Paul.

A voter at a rally expressed concern that the former Massachusetts governor hadn't spent enough time in Iowa to deserve winning the state's caucuses. Some of his rivals, including Rick Santorum and Michele Bachmann, have focused on Iowa since summer while Romney has only visited Iowa eight times all year — three times for televised debates.

Romney responded: "I hope, as you look at the people running, you can measure their capacity to lead effectively and you can also determine whether they can become our nominee and defeat President Obama. ... I think I can."

The Iowa caucuses, Romney told a crowd of several hundred gathered in Mason City's Music Man Square, are about "selecting who our nominee ought to be."

As part of his stepped-up campaign, Romney began running an upbeat, minute-long ad on TV that features portions of his June announcement speech. He was midway through a bus tour of eastern Iowa that ends Friday in Des Moines.

Romney planned to campaign in New Hampshire Friday night and Saturday morning — but then return to Iowa and stay through the caucuses Tuesday night. He was set to hold a series of events on the economy in western Iowa, followed by six campaign rallies, mostly in eastern Iowa, from Sunday through Tuesday, including an early morning one before voters start gathering to declare their candidate preferences.

Romney was spending caucus night in Des Moines before flying to New Hampshire on Wednesday morning.

His six rallies begin New Year's Day in Council Bluffs, in the western part of the state. In 2008, he did well in nearby counties where agribusiness drives the economy. He'll hold another set of rallies in eastern Iowa, where he also performed well.

Romney spent Thursday largely ignoring his Republican rivals in the state, instead focusing on attacking President Barack Obama.

"We have a choice in this coming election of what kind of America we're going to have," he told the crowd at J's Homestyle Cooking. "It's not just about replacing a president. It's about saving the soul of America. Are we going to change America into something we don't recognize?"