Once bitter rivals for the presidency, Mitt Romney and John McCain campaigned together as friends on Friday, one gearing up for a likely presidential bid and the other fighting to hold onto his seat in the U.S. Senate

The two Republicans fielded questions from a largely supportive audience of several hundred people, touching on issues including immigration and the environment while heaping criticism on President Barack Obama

Romney, the former Massachusetts governor, battled with McCain in 2008 for the Republican nomination for president, then aggressively campaigned for McCain in the general election. He has endorsed the Arizona senator in his current re-election bid

McCain is being challenged in the Aug. 24 primary by former U.S. Rep. J.D. Hayworth, a former television sportscaster and talk-radio host who hopes anti-Washington sentiment and McCain's past high-profile work with Democrats can help him knock off the four-term senator

Neither McCain nor Romney mentioned Hayworth on Friday, instead directing their criticism at Obama

"This is an administration that is governing from the far left, and America is a right of center nation," McCain said before ticking off various Obama policies he opposes, including bailouts of the auto industry and health care reform

Romney said McCain's clout after 28 years in Congress is important in fighting the Obama administration

"He's a Washington heavyweight," Romney said of McCain. "He knows how to push back against the Obama machine."



The Democratic National Committee highlighted the former tensions between the rivals, releasing a Web video Friday featuring some of their barbs on national television

McCain opened the town hall meeting with a nod to their "spirited campaign," but suggested Romney was gracious in defeat

"After that primary was completed, there was no one person who worked harder on behalf of our ticket and the things that we believe in than Mitt Romney," McCain said.