OSKALOOSA, Iowa (AP) - President Barack Obama and Mitt Romney sparred over energy policy Tuesday, adding state-specific issues to a contest otherwise focused on the weak economy.
Obama mocked Romney's stance on wind power while Romney accused the president of waging a "war on coal."
The emphasis on the economy continued, however. A new Obama television ad and Vice President Joe Biden assailed GOP budget plans to overhaul Medicare, cut trillions of dollars from domestic programs including education and lower taxes on high-income taxpayers.
Romney's camp replied with their own TV spot casting Obama as a danger to seniors.
In Iowa, a center of wind energy production in the United States, Obama noted that Romney once dismissed wind power by saying "you can't drive a car with a windmill on it."
"I don't know if he's actually tried that. I know he's had other things on his car," Obama joked, referring to the often-repeated tale of a Romney family road trip with their dog, Seamus, in a carrier strapped to the roof of the car. "But if he wants to learn something about wind, all he's got to do is pay attention to what you've been doing here in Iowa."
Romney, campaigning in coal-rich eastern Ohio, said Obama was misleading Ohio voters by claiming new jobs in coal producing regions. He also promised to make the U.S. independent from Venezuelan and Middle Eastern oil.
"By the end of my second term, I'll make this commitment: We will have American, we will have North American energy independence," Romney said at a coal mine in Beallsville. "We won't have to buy oil from Venezuela and the Middle East. We're going to be independent."
Standing not far from a bulldozer filled with coal and decorated with a sign that read, "Coal Country Stands With Mitt," Romney accused Obama of lying to voters in this coal-rich region.
"He (Obama) talks about how wonderful it is and how we're adding jobs in the coal industry and adding more coal," Romney said. "I thought, you know, how in the world can you go out there and just tell people things that aren't true. This is a time for truth. If you don't believe in coal, if you don't believe in energy independence, then say it."
The energy fight played amid the different interests of the candidates' respective audiences.
The federal government says between 6,000 and 7,000 jobs in Iowa are related to the wind industry and that the state gets about 20 percent of its electricity from wind. In a bipartisan vote last week, the Senate's tax-writing committee agreed to renew dozens of tax breaks for businesses like biodiesel and wind energy producers, provisions opposed by many conservatives but that also have won critical support from some Republicans, like Sen. Charles Grassley of Iowa.
"Unlike my opponent, I want to stop giving $4 billion in taxpayer subsidies each year to big oil companies that have rarely been more profitable, and keep investing in homegrown energy sources like wind that have never been more promising," Obama told a crowd of about 850 people in Oskaloosa, where stacked hay bales and an old, red pickup truck provided the requisite rural backdrop.
Romney has opposed extending the alternative energy credits, but several Iowa Republicans - Iowa Gov. Terry Branstad and Grassley among them - favor the credits.
That opposition is giving 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."
In the coal regions of eastern Ohio, the Obama administration is blamed for pushing ahead with regulations on new power plants that make it harder to build new coal-fired plants that have hurt places like Beallsville.
"To win Ohio, he's got to win eastern Ohio, and he's got to get the votes of people in communities all around us here," Romney said. "And you're not going to let that happen."
The presidential contest moved across five swing states Tuesday, with both campaigns operating on full strength for a second day. Romney was on his final day of a multistate bus tour, with three stops in Ohio.
Running mate Paul Ryan, the Wisconsin congressman, was dispatched 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.
Vice President Joe Biden kept up his criticism of the Republican ticket and its support for a House GOP budget plan, telling supporters in rural southern Virginia that Romney and Ryan are "good men" but with "fundamentally flawed judgment."
Biden prompted a Republican backlash when he said the Republican candidates and GOP lawmakers would put them "back in chains" by getting rid of financial industry regulations Obama signed into law.
Said Biden: "Unchain Wall Street. They're going to put y'all back in chains."
Romney spokeswoman Andrea Saul said Biden's comments are "not acceptable in our political discourse" and a "new low."
An Obama campaign official said it was clear that Biden was talking about the risks of letting Wall Street operate without strong oversight.
Meanwhile, Ryan was to promote Romney's "all-of-the-above" energy approach during his event in Lakewood, Colo., before heading to Las Vegas to highlight Obama's response to the state home foreclosure crisis.
The congressman also was expected to attend a private fundraiser with conservative mega-donor Sheldon Adelson. Also Tuesday, Obama's campaign launched its first television advertisement since Ryan joined the GOP ticket.
The ad, which seeks to link Romney to proposed domestic spending cuts in Ryan's austere budget proposal, criticizes Romney for backing plans that would cut college financial aid for nearly 10 million students.
That's the same criticism the White House has long leveled against Ryan's budget cuts.
Ryan has said Pell grants would still be funded under his budget. The ad is running in Colorado, Iowa, Nevada, Ohio and Virginia.
Romney's camp promptly responded with an ad accusing Obama of cutting $700 billion from Medicare to pay for his health care plan.
Eager to defend Romney from Obama attacks that Republicans intend to alter Medicare, the ad states: "The Romney-Ryan plan protects Medicare benefits for today's seniors and strengthens the plan for the next generation."