TAMPA, Fla. -- They're the political world's newest odd couple: Mitt Romney and Paul Ryan are bound by substance, but differ dramatically in style.
The running mates share a love of policy, and a fascination with the world's economy and America's place in it. But where Romney is buttoned-up and reserved on the campaign trail, Ryan is relaxed and exudes a natural enthusiasm.
Romney, the former Massachusetts governor who once supported abortion rights and more liberal gay policies, has struggled to convince some Republicans of his conservative credentials. Ryan, the architect of an austere congressional budget blueprint, is a hero of the right.
As Ryan prepared to address the Republican National Convention on Wednesday night, the looming question was whether he'd steal the spotlight from Romney, who speaks Thursday.
So far, Romney has tried to share in his running mate's appeal rather than seek to outshine him. His campaign pared back plans for them to campaign separately in the run-up to the Tampa convention and instead scheduled more joint events.
Appearing together, Romney and Ryan drew crowds of up to 7,000 people, dwarfing Romney's largest solo event last week -- a speech to 1,600 at a manufacturing facility in Bettendorf, Iowa. And Romney, who is often restrained and cautious in the public eye, is clearly more ebullient and relaxed alongside Ryan, who campaign aides have dubbed "the partner."
"I am so happy! I am so happy to have my teammate now," Romney told cheering supporters during one of their first rallies together in Mooresville, N.C.
Ryan, for his part, said he had expected the demands of the campaign to be draining but instead "it's more energizing."
The 42-year-old Ryan has an obvious comfort on the campaign trail that Romney does not. He wears cowboy boots, skips up stairs two at a time and makes frequent sports references, including shout-outs to his beloved Green Bay Packers.
He also likes to poke fun at himself.
"We do cow-milking contests in Wisconsin," he told supporters at the Iowa State Fair earlier this month. "I usually lose to a 17-year-old woman, who grew up on a dairy farm, who's wearing like a sash and tiara."
There also is evidence of Ryan's active lifestyle wherever he goes. A former personal trainer, he works out at his hotel gym almost every morning. And he sprinkles his campaign speeches with mentions of hunting, skiing and hiking.
Romney struggled to connect with gun rights' advocates, for example, at one point saying he hunts "small varmints." Ryan, on the other hand, did an interview for Deer and Deer Hunting's October issue, telling the magazine that one of his goals is to hunt sheep with a bow.
"I don't know if I'll ever be able to try, but one of my goals is to get a grand slam of sheep with a bow," Ryan told the magazine. "It would be very tough and very expensive. But I'd love to do some of those great western hunts for sheep and deer."
Romney shares few personal stories in his campaign speeches and his interactions with voters are more measured. His most animated moments in front of a crowd often involve little more than a wave and a smile.
Despite their different personalities, Romney and Ryan both are data-driven thinkers who see themselves as problem-solvers -- and good ones at that. They view Romney's work in the private sector and Ryan's congressional budget expertise as complementary experiences that would serve them well in the White House.
Romney aides say they always expected Ryan to be a popular choice. And they dismiss the notion that having an attention-grabbing running mate could be problematic for the campaign.
"When they're together, the energy they create with voters is very apparent," said Kevin Madden, a Romney adviser. "They have a great rapport together that really helps as we travel from one event to the next and from one state to another."
Still, the campaign is well aware of the problems that cropped up when past running mates garnered too much attention or were trusted prematurely to play a prominent role in the campaign. Alaska Gov. Sarah Palin infused John McCain's campaign with energy in 2008, but proved to be more of a distraction than an asset.
Charlie Black, a senior adviser to McCain's campaign, said he doesn't expect Ryan's popularity to become a liability for the Republican ticket.
"It's not a problem if the person stays on message," said Black, now an informal Romney adviser. "And Paul Ryan is going to stay on message."
Even as Romney seeks to benefit from Ryan's spotlight, he is distancing himself from some of his running mate's most controversial policy proposals. Embracing those positions could boost Romney's standing with conservatives, but also turn off more moderate voters.
Romney has repeatedly said the ticket was running on his budget proposals, not the budget Ryan crafted that calls for slashing spending and overhauling Medicare, the popular federal program for seniors. On abortion, the campaign says a Romney administration would not oppose abortion in cases of rape and incest, while Ryan opposes it in those situations.
Democrats, however, are doing their best to make Ryan -- and his controversial budget proposals -- the center of attention. President Barack Obama points to Ryan as the Republican party's "ideological leader." His campaign, in a play for seniors and middle-class voters, is running ads casting Ryan's proposals for overhauling Medicare and drastically cutting other social programs as outside the mainstream.
Democrats also have rebranded Ryan's budget the "Romney-Ryan" plan. They're also using Ryan's views on abortion to link the GOP ticket to Todd Akin, the Republican Senate candidate in Missouri who said women's bodies can prevent pregnancies in cases of "legitimate rape."