CINCINNATI, OHIO - In battleground states across the country, President Obama and Mitt Romney pressed voters to their sides on Thursday, with the incumbent arguing that he was the candidate voters could trust and the challenger insisting that he represented needed change.

With Election Day less than two weeks away, their campaigning crackled with urgency. Obama continued on a non-stop two-day tour of several battleground states, moving from Nevada overnight to Florida in the morning, and later to Virginia, Illinois - where he voted - and on to Ohio. Romney spent the day in that state, chief among those in the candidates' sights as Nov. 6 nears.

It was a day of deeply contrasting messages that hinted at the moods and strategies inside both campaigns: Romney sought to keep projecting the air of a winner, focused on an ambitious agenda of reform, while Obama emphasized the gritty mechanics of shoring up his electoral turnout.

At a rally in Ybor City, Fla., Obama, his voice already hoarse, delivered a direct pitch to women voters. As he urged the 8,500 supporters to head to the polls, he told them electing a president was about trust. "When you elect a president, you're counting on someone you can trust to fight for you," Obama said. "Trust matters."

'We want big change'

The president won the endorsement of former Secretary of State Colin Powell, who told "CBS This Morning" that he was "more comfortable" with the president's views on immigration, education and health care. He praised the president's handling of national security and said he was concerned that Romney was "a moving target" on foreign policy.

He said, "There are some very, very strong neo-conservative views that are presented by the governor that I have some trouble with."

He said he still considered himself a Republican but in "a more moderate mold." He added, "That's something of a dying breed, I'm sorry to say."

Meanwhile, Romney took a page from Obama's campaign four years ago as he told voters that he was the candidate of "big change." At his first of three rallies on his bus tour, he mentioned the phrase "big change" no fewer than a dozen times.

"The president has the same old answers as in the past -- he wants another stimulus, he wants more government workers, and he wants to raise taxes," he said. "We want real change. We want big change."

For Obama, reclaiming the change mantle as an incumbent has been one of his singular challenges. It is hard to run against Washington while traveling with an armed entourage and a big blue and white government plane. So the president has alternated between blaming Republicans in Congress for blocking change and arguing that the change Romney represents is actually more of the same policies from the Bush era.

'We guard the change'

At an Obama rally in Richmond, Va., on Thursday, Sen. Mark R. Warner, a Democrat, summarized the argument in pithy form. "In 2008, we changed the guard," he told a crowd of 15,000 who turned out to see the president. "In 2012, we guard the change."

Obama made the case that change has been slower than anyone might wish but that it is under way. "We've got a long way to go, but, Florida, we've come too far to turn back now," Obama said. "We can't afford to go back to the same policies that got us into the mess."

Romney's new message of change highlights how significantly his pitch to voters has evolved since he entered the race in 2011. Back then, he devoted most of his time to attacking the president's economic stewardship, even mocking the idea of big change: A standard line back then criticized Obama as trying to "transform America" away from an opportunity society. On Thursday, it was Romney who called for transformation, of the small-government variety, saying that Obama stood for "the status quo path."

The New York Times contributed to this report.