By Steve Holland and Samuel P. Jacobs
DAYTON, Ohio (Reuters) - Facing a tough path to victory if they cannot win Ohio, Republicans Mitt Romney and Paul Ryan launched a two-day bus tour on Tuesday to try to boost their fortunes in a state that polls show could be slipping away from them.
The Republican nominees for president and vice president appeared together for the first time in more than three weeks, part of what aides vow will be a more aggressive phase of campaigning after Romney spent much of the past two weeks raising money and holding few public rallies.
Romney emphasized his claims that Democratic President Barack Obama's policies are preventing the U.S. economy from a full recovery and that Obama has not been tough enough in pushing back against Chinese trade practices that have led to cheap goods flooding the U.S. market and killing American jobs.
Romney accused China of a wide variety of trade abuses, from holding down the value of its currency to keep its products cheap, to stealing U.S. intellectual property.
"We cannot compete with people that don't play fair, and I will not let that go on," Romney said.
SCRAMBLING IN OHIO
Romney's message on China has been a central part of his stump speech all year. Obama's campaign has responded with a television ad that accuses Romney of outsourcing jobs to China during his time as a private equity executive at Bain Capital.
Romney and his team hope the trade message will resonate in Ohio, a politically divided state that is key to his chances of winning the presidency - but where polls indicate Obama has opened up a lead.
Ohio's unemployment rate in July was 7.2 percent, better than the national level of 8.1 percent.
It is difficult to see how Romney could win the November 6 election without Ohio.
He has a narrower path than Obama to get the 270 electoral votes needed for victory, and most scenarios require him to win the Midwestern state where thousands of jobs were saved by the Obama-backed government bailout of the auto industry.
Romney aides dismissed surveys showing the Republican presidential ticket falling behind Obama in Ohio on a day in which a Washington Post poll showed the president with an 8-point lead over Romney, 52 to 44 percent.
Romney political director Rich Beeson told reporters on the candidate's plane that the campaign's internal polling showed a closer race in Ohio, within the survey's margin of error. He accused the Obama campaign of "spiking the ball at the 30-yard line," or declaring victory in the state long before the election.
"I kind of hope the Obama campaign is basing their campaign on what the public polls say," Beeson said. "We don't. We have confidence in our data and our metrics."
'MORE AGGRESSIVE, ASSERTIVE'
Romney has suffered a series of stumbles in recent weeks that have knocked him off message and given the advantage to Obama.
Some Romney supporters hope their candidate will put that behind him with an aggressive campaign schedule in the 10 or so key states that will decide the outcome of the election.
"I would like him to be more aggressive, assertive in detailing his plans, making people vote for a future and not against an alternative future. I want him to focus more on what he's going to do," said Ken Warner, 50, a software engineer from South Dayton, Ohio.
Romney sought to generate some fresh energy by appearing with Ryan, a Wisconsin congressman and budget hawk who is popular among conservatives - many of whom have been disappointed that Ryan has not been a more prominent force in Romney's campaign.
In introducing Romney, Ryan pointed to Romney's experience in the business world and said Obama is trying to distract Americans' attention from the economy.
"This president cannot run on his record. This president is going to say anything and everything to try and blame, to try and duck, to try and distort, to try and divide, to try and distract," Ryan said. "You know what, Ohio? We're not going to let him."
Joining Romney and Ryan on stage were two Republican senators, Rob Portman of Ohio and Rand Paul of Kentucky. Paul is the son of Ron Paul, a Texas congressman who ran against Romney for the Republican presidential nomination and has declined to endorse Romney.
Portman was on Romney's short list to be the vice presidential running mate. Now he is playing the role of Obama in mock debate sessions that Romney has been conducting to prepare for three presidential debates that may prove decisive in the election. The first one is on October 3 in Denver.
Romney quipped that Portman is playing the role of Obama well.
"I want to kick him out of the room, he's so good," Romney said to laughter.
(Editing by David Lindsey and Eric Beech)