"It's likely that they'll be campaigning on different tracks until we get to the convention," Romney senior adviser Kevin Madden told reporters after North Carolina crowds swelled to 8,000 and grew more noisy Sunday as the two men campaigned together.
The convention -- when GOP delegates choose the party's nominees for president and vice president -- is to be held in Tampa, Fla., the week of Aug. 27.
Wisconsin native Ryan, 42, the House Budget Committee chairman, was to attend the Iowa State Fair in Des Moines Monday, while Romney was to go to St. Augustine, Fla., and Miami, campaign officials said.
"We have a number of states that are competitive where we believe he helps us," Madden said of Ryan. "Obviously, his home state of Wisconsin and some of these other Great Lake states. But Iowa in particular -- that is a state where I think his life story is important for others, something that I think helps him connect with a lot of those voters there."
Madden denied Ryan's not being in Florida Monday had anything to do with his controversial proposals to privatize part of Social Security and replace Medicare with a voucher program for future senior citizens.
"This has more to do with expanding our bandwidth," Madden said.
Ryan is expected to be in central Florida next weekend, aides said late Sunday.
"President Obama came into office with hope and change," Ryan said at a High Point, N.C., rally with Romney. "His policies have been put in place. They are not working. They are failing us. He didn't moderate one bit at all. So now he's turned hope and change into attack and blame, and we're not going to fall for it."
He touted Romney, recalling the 2002 Winter Olympics in Salt Lake City, plagued by a 1998 bribery scandal and a financial shortfall, which Romney left Bain Capital to oversee in 1999.
"Remember the chaos? Remember the waste, the bloated spending, the corruption? Who did they turn to? Who did they ask to turn it around? This guy right here," Ryan said, pointing to Romney standing near him.
Romney raised millions of dollars from Mormon families to help finance the Olympics. The Games also received an additional $410 million from Washington.
Concerning Medicare, Romney told the CBS program "60 Minutes": "What Paul Ryan and I have talked about is saving Medicare, is providing people greater choice in Medicare, making sure it's there for current seniors.
"No changes, by the way, for current seniors, or those nearing retirement," Romney said. "But looking for young people down the road and saying, 'We're going to give you a bigger choice.' In America, the nature of this country has been giving people more freedom, more choices. That's how we make Medicare work down the road."
President Barack Obama was expected to be in Iowa himself Monday -- about 130 miles west of Ryan -- beginning a three-day Hawkeye State bus tour.
He was to start in Council Bluffs, on the east bank of the Missouri River across from the much larger city of Omaha, Neb., then go due east to 13,000-population Boone, near Ames, the White House said Sunday night. Obama is to reach Dubuque and Davenport by Wednesday.
During a fundraiser in Chicago Sunday, Obama called Ryan the "ideological leader of Republicans in Congress."
"I want to congratulate Mr. Ryan. I know him. I welcome him to the race," Obama said. "He is a decent man, he is a family man, he is an articulate spokesman for Governor Romney's vision -- but it is a vision that I fundamentally disagree with," Obama said in his first public remarks about Romney's vice presidential choice.
Obama senior campaign adviser David Axelrod told ABC's "This Week" Ryan's selection as Romney's running mate was "meant to thrill the most strident voices in the Republican Party, but it's one that should trouble everybody else -- the middle class, seniors, students."
He called Ryan "a right-wing ideologue" and "the intellectual energy behind the Republican caucus there in Congress."
"He constructed a budget that, like Romney, would lavish trillions of dollars of tax cuts, most of them on the wealthy, would raise the burden on the middle class, would cut back things deeply like student loans, and research and development, and things we need to grow the economy," Axelrod said.
"He's the guy who's the architect of a plan to end Medicare as we know it and turn it into a voucher program and ship thousands of dollars of costs onto senior citizens," Axelrod said. "He's someone who was the architect of a Social Security privatization scheme that was so out there that even George Bush called it irresponsible, and he believes that we should ban abortion even in cases of rape and incest."
He told CNN's "State of the Union" he considered Ryan a "good person -- you know, genial person -- but his views are quite harsh."
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