DENVER -- The newly shaped Republican presidential ticket is fighting growing pains amid charges from President Barack Obama's re-election team that challenger Mitt Romney favors his new running mate's plans to overhaul Medicare, cut trillions of dollars from social programs and lower taxes on high income taxpayers.
The debate moved across five swing states as both campaigns operate at full strength for a second day.
Romney was spending Tuesday in Ohio on the final day of his multistate bus tour, having dispatched his vice presidential pick, Wisconsin Rep. Paul Ryan, to court voters and donors in Colorado and Nevada. For all the advantages of having a running mate to share the workload, the Republicans are working through the challenge of planning double the events, coordinating messaging on the road, handling new security stresses and simply getting to know each other.
All the while, Obama and Vice President Joe Biden are linking Romney to Ryan's House Republican budget proposals, which could affect millions of Americans - seniors in particular - if enacted.
Biden kept up his criticism of the Republican ticket Tuesday, telling supporters in rural southern Virginia that Romney and Ryan are "good men but they have fundamentally flawed judgment."
Obama was holding events in Iowa, the second day of a three-day bus tour across that highly competitive Midwestern state.
Two days after formally selecting Ryan to complete the GOP ticket, Romney publicly praised his running mate's work as necessary to protect the long-term survival of Medicare, the government-run health insurance program for the elderly.
Ryan has "come up with ideas that are very different than the president's," Romney said in Florida, the state with the highest percentage of residents age 65 and over. "The president's idea for Medicare was to cut it by $700 billion. That's not the right answer. We want to make sure that we preserve and protect Medicare."
Romney did not say so, but the plans Ryan produced in the past two years as chairman of the House Budget Committee retain the $700 billion in Medicare cuts even as they call for repealing Obama's health care plan. Romney said there may be differences between his own budget plan and Ryan's, but refused to detail them. Romney's staff said the former Massachusetts governor favored a plan to restore the $700 billion in cuts.
Looking to move past questions about Medicare, both Romney and Ryan are expected to focus on energy Tuesday. Romney will address what he's calling the Obama administration's "war on coal," according to his campaign. Ryan plans to promote Romney's "all-of-the-above" energy approach in Colorado. Once he moves to Nevada later in the day, Ryan will also highlight the president's response to the state's foreclosure problems.
Little more than 80 days remain in a campaign dominated by a weak economic recovery and a national jobless rate of 8.3 percent. Polls taken before Romney added Ryan to his ticket showed Obama with a slender advantage in a contest that will be decided in eight to 10 battleground states.
Romney planned three events across Ohio, starting in the eastern part of the state and continuing westward.
He will focus on coal in the area of the state near the West Virginia border. Obama's administration has pushed ahead with regulations on new power plants, making it harder to build new coal-fired plants. That's hurt places like Beallsville, where Romney will appear at the American Energy Corp.
Romney planned to appear in Ohio with Republican Sen. Rob Portman, whom Romney considered as a possible vice presidential running mate.
Ohio is likely the most difficult to win of the four must-win states Romney toured by bus; he also visited North Carolina, Virginia and Florida. But as Ryan visits other battlegrounds more than 1,000 miles away, Romney's team has showed some signs of the strain:
-Some of Romney's staff on the ground in Florida were on the phone Monday offering advice to the Ryan team in Iowa, while planning events coming up in Colorado and Nevada.
-There were none of the new Romney-Ryan placards at Romney's Florida event or Ryan's Iowa appearance Monday, leaving attendees waving the older Romney-only signs.
-Security officials didn't set up enough metal detectors to sweep the thousands of people who showed up in Florida, leaving many stranded outside barricades or on the street.
-At the Iowa State Fair, a protester managed to climb onstage with Ryan before his new security team dragged her away.
Ryan is scheduled to campaign at a Denver area high school Tuesday before addressing a rally in Las Vegas. The congressman is also expected to attend a private fundraiser with conservative mega-donor Sheldon Adelson.
Meanwhile, plans continued for the Republican convention in less than two weeks in Tampa, Fla., amid word that New Jersey's Gov. Chris Christie has been selected to be the keynote speaker.
The scheduling decision was confirmed by Republican officials directly involved in convention planning. The Republican officials spoke on the condition of anonymity because the formal announcement was not planned until later Tuesday.
The Romney campaign also said Tuesday that Florida Sen. Marco Rubio will introduce Romney at the convention. Rubio campaigned with Romney in Miami on Monday. Before Ryan's selection, both Rubio and Christie had been under consideration to join the GOP ticket as Romney's running mate.
For his part, Obama is expected to call on Congress to extend expiring tax credits for wind energy production. The White House on Tuesday pointed to a new Energy Department report saying wind power installations "surged" in 2011, but warning that uncertainty over extending the wind energy tax credits threatens to "dramatically slow" the industry.
The report, released annually, emerged just as Obama was campaigning through politically competitive Iowa, a state that is among the leaders in wind power. The report estimated 75,000 U.S. jobs now depend on wind power. Of those, state officials say, 7,000 are in Iowa.
Romney has opposed extending the alternative energy credits, but several Iowa Republicans - Iowa Gov. Terry Branstad and Sen. Chuck Grassley among them - favor the credits. That may give Obama the chance to create a local wedge issue to appeal to unaligned voters.
Romney spokesman Ryan Williams said the Republican candidate would boost the wind industry by "promoting policies that remove regulatory barriers, support free enterprise and market-based competition, and reward technological innovation."
The Obama campaign also released a Web video Tuesday chiding Romney for ads in which he accused the White House of stripping work requirements from the welfare law. Independent fact checkers have found the premise of the ads to be false.
The Obama video shows Romney asking his opponent to "take your campaign out of the gutter." Then it urges, "Mr. Romney ... take your own advice."
Hunt reported from Florida. Associated Press writers Matthew Daly in Virginia and Ken Thomas in Iowa contributed to this report.