Mitt Romney and Paul Ryan kick off Ohio bus tour The tour comes as a new Post-ABC poll shows Obama leading Romney 52 percent to 44 percent among likely Ohio voters. The survey not only shows Obama taking a lead in the race for Ohio's 18 Electoral College votes, but it also suggests that voters" opinions have hardened six weeks out from Election Day: Eighty-five percent of likely Ohio voters who plan to vote for Obama and 86 percent who are backing Romney say they'll "definitely" vote for their chosen candidate. That means that the campaigns" ability to energize their respective bases could matter more than whether they're able to woo the relatively small number of undecided voters. It also helps explain why the Romney-Ryan ticket has enlisted Sen. Rand Paul (R-Ky.), a tea party favorite, to join them at Tuesday night's event. Vandalia is in Montgomery County, which voted 52 percent to 47 percent for Obama over Sen. John McCain (R-Ariz.) in 2008. At a solo campaign event in Lima, Ohio, on Monday, Ryan took aim at Obama on foreign policy, casting blame on the president for looming bipartisan defense cuts and telling a crowd that the current unrest in the Middle East "reminds you of 1979 Tehran," referring to the seizure of the U.S. Embassy there and the 52 Americans who were held hostage for 444 days. Romney will join Ryan in Ohio after his address to the Clinton Global Initiative in New York. Meanwhile, Obama was in New York to address the United Nations. In his remarks to the Clinton Global Initiative, Romney did not mention Obama, although he used his speech to suggest that the current U.S. foreign aid system has failed. "I became convinced (while traveling abroad for Bain Capital) that the crucial difference between these countries wasn't geography," Romney said. "I noticed the most successful countries shared something in common," Romney continued. They were the freest. They protected the rights of the individual. They enforced the rule of law. And they encouraged free enterprise. They understood that economic freedom is the only force in history that has consistently lifted people out of poverty - and kept people out of poverty. Romney in recent days has shifted his criticism of Obama from domestic to foreign policy, perhaps sensing an opening in the wake of this month's attacks on U.S. diplomatic missions in the Middle East. Democrats, by contrast, have zeroed in on domestic issues, including GOP proposals to cut taxes for wealthier Americans and Romney's decision not to release more of his tax returns. In a conference call with reporters Monday, Romney adviser Ed Gillespie dismissed criticism that the campaign has not been focused enough on a single message. We are talking about the economy and the need for more jobs and more take-home pay, and we have been talking about that for some time. . . . We are going to comment on the news of the day to the extent that it warrants a response. We try to keep it consistent, choice versus referendum," Gillespie said. Democrats, meanwhile, are kicking off their own bus excursion - the "Mitt Romney: Writing Off the Middle Class" tour, which will shadow Romney and Ryan in Ohio. The tour, led by former Ohio governor Ted Strickland (D) and Brad Woodhouse, communications director for the Democratic National Committee, will remind voters of comments Romney made at a closed-door fundraiser regarding the "47 percent" of Americans who don't pay income tax and see themselves as "victims" entitled to government help. Obama is scheduled to be Ohio on Wednesday for events in Bowling Green and Kent. Nia-Malika Henderson and Rachel Weiner contributed to this report.