DAYTON, Ohio (AP) ― President Barack Obama and Mitt Romney plunged into the final two weeks of an excruciatingly close race for the White House, with Obama accusing his Republican challenger of changing his positions so often he can’t be trusted.

The two are neck-and-neck, and Romney presented a more centrist approach to foreign policy during a Monday night debate ― the last of three, and that one on foreign policy. The Republican’s performance, however, gave the Obama campaign more ammunition to allege that Romney is willing to shift from or lose his more conservative positions to satisfy his more mainstream constituents.

“We are accustomed to seeing politicians change their position from four years ago,” Obama told a Florida rally Tuesday. “We are not accustomed to seeing politicians change their positions from four days ago.”

By abruptly moderating his foreign policy positions, Romney is hoping to neutralize one of Obama’s main strengths with the election only two weeks away. But the move toward the political center comes with potential pitfalls.

By abandoning several of his sharpest criticisms of Obama from the past several months, Romney risks upsetting some conservatives and reinforcing the allegation ― levied repeatedly by the president during the debate on Monday night ― that his positions lack conviction and leadership.

Obama’s campaign released a 20-page booklet called the “Blueprint for America’s Future” on Tuesday to promote a second-term agenda, responding to Republican criticism that the president has not clearly articulated a plan for the next four years. The plan includes spending more on education, boosting manufacturing jobs and raising taxes on the wealthy.

Neither side can claim the lead at this late stage of the race, with polls showing the race virtually tied nationally and in some of the key states. Obama’s challenge is to convince voters who may be hurting financially that he is better qualified to lead the country back to economic prosperity than Romney, who made a fortune as a successful businessman. Romney has exuded confidence on the campaign trail following his strong performance in the first debate on Oct. 3.

Obama was campaigning in Florida and Ohio, two of nine battleground states that do not reliably vote for one party or the other, and that therefore will decide the election. The U.S. president is not chosen according to the popular nationwide vote but in state-by-state contests.

With the final debate behind them, the economy ruled the day. Obama brandished a new 20-page summary of his second-term agenda and told a campaign crowd in Florida his rival’s blueprint “doesn’t really create jobs. His deficit plan doesn’t reduce the deficit; it adds to it.”

Later Tuesday, the president joined Vice President Joe Biden in what is likely to be the most crucial battleground state of all, Ohio.

In Dayton, Obama said of his rival: “In the closing weeks of the campaign, he’s doing everything he can to hide his true positions. He is terrific at making presentations about stuff he thinks is wrong with America, but he sure can’t give you an answer about what will make it right. And that’s not leadership you can trust.”

Obama advisers see the new approach as a way to capitalize on polls that show voters see the president as more trustworthy than Romney. A Washington Post/ABC News poll last week showed 55 percent of likely voters said Obama is “honest and trustworthy” compared to 47 percent who felt that way about Romney.

Romney and running mate Paul Ryan’s schedule reflected the strategy of driving up Republican vote totals in areas such as the Denver suburbs of Colorado and Cincinnati, Ohio.

The challenger began his final two-week sprint in Nevada, where he told a large, cheering crowd in Henderson that Obama wants a new term for the same policies that have produced slow economic growth and high unemployment for four long years. “He is a status quo candidacy. ... That’s why his campaign is slipping and ours is gaining so much steam,” he said.

Romney’s aides dismissed Obama’s 20-page booklet as nothing new, and the former Massachusetts governor said of the president, “His vision for the future is a repeat of the past.”

During Monday night’s debate, Romney largely expressed agreement with how Obama has conducted U.S. foreign policy. He dramatically shifted his position and agreed with the president that all U.S. forces should be out of Afghanistan by the end of 2014. Romney previously had criticized Obama for setting such a date for withdrawal, saying he was giving the Taliban insurgency and its al-Qaida allies a date after which the militants could begin a drive to retake the country. Romney also dropped the conditions he had set for troop withdrawal.

Romney even congratulated Obama “on taking out Osama bin Laden and taking on the leadership of al-Qaida,” but he added, “We can’t kill our way out of this mess. ... We must have a comprehensive and robust strategy.” He did not offer specifics.