President Barack Obama is blaming Republican vice presidential candidate Paul Ryan for blocking a farm bill that could help voters in Iowa and elsewhere cope with a crippling drought, as both candidates campaigned in the important Midwestern battleground.

"If you happen to see Congressman Ryan, tell him how important this farm bill is to Iowa and our rural communities," Obama says in excerpts released before he spoke Monday in Council Bluffs, Iowa.

Ryan, campaigning alone for the first time since getting the vice presidential nod, planned to meet voters Monday at the Iowa State Fair. Romney was in Florida for a bus tour.

Obama carried Iowa in 2008, but polls show a close race in the battleground state less than three months from Election Day.

Ryan's events in Iowa could help determine whether conservative excitement for the Wisconsin congressman _ and his austere budget plans _ will overshadow Romney's message and Republican attacks on Obama's economic performance.

Romney briefly defended his new running mate's budget proposals for Medicare, telling Florida voters that the Republican ticket wants to "make sure that we preserve and protect Medicare."

"He's come up with ideas that are very different than the president's," Romney said of Ryan. "The president's idea, for example, for Medicare, was to cut it by $700 billion. That's not the right answer."

At the same time, a pro-Romney super PAC is spending more than $10 million on a new television advertisement attacking Obama's handling of the economy as the nation's unemployment rate lingers above 8 percent.

"Another month. Even more Americans jobless," says the narrator in the ad from the group, Restore Our Future, which is led by people with close ties to Romney.

The spot will air for more than a week across 11 presidential battleground states, including Colorado, Florida, Iowa, Michigan, Nevada, New Hampshire, North Carolina, Ohio, Pennsylvania, Virginia and Wisconsin.

Democrats are banking on Ryan and his controversial budget proposals overshadowing Romney's message and Republican attacks on Obama's economic performance.

Since Romney formally named Ryan his running mate on Saturday, the Obama campaign has been attacking the Republican budget architect's plans to transform Medicare into a voucher system and re-shape the nation's tax system.

A top Obama political adviser, David Axelrod, said Monday that Romney's selection of Ryan is reminiscent of John McCain's choice of Sarah Palin four years ago. He told "CBS This Morning" he remembers the initial excitement surrounding Palin's selection, but says he doesn't believe the choice of Ryan "is going to be a plus for Mr. Romney."

Axelrod called Ryan "a genial fellow" who advocates harsh policy positions, particularly on Medicare.

Ryan figures to play prominently in Obama's message during his three-day bus tour across Iowa, which marks his longest visit to a single state during the 2012 campaign.

Obama's bus tour will begin in Council Bluffs, just across the Missouri River from Omaha, Neb., and head across the state before wrapping up in Davenport along the Mississippi River.

Obama will showcase the powers of incumbency as he tours a farm in Missouri Valley, Iowa, and discuss ways of addressing the devastating drought. White House officials said the president planned to direct his Agriculture Department to buy up to $170 million worth of meat and poultry to provide relief to farmers and ranchers.

The Defense Department, a large purchaser of beef, pork and lamb, was expected to look for ways to encourage its vendors to speed up purchases of meat.

Obama has urged Congress to pass a farm bill to provide a long-term solution for farmers. Democrats and Republicans are at odds over the program's farm subsidies and food stamps, with Ryan among the GOP lawmakers backing cuts in food stamp programs that are opposed by the president's party.

Ryan, a 42-year-old congressman, is best-known for his proposing to reshape Medicare, the long-standing entitlement, by setting up a voucher-like system to let future retirees shop for private health coverage or choose the traditional program _ a plan that independent budget analysts say would probably mean higher out-of-pocket costs for seniors.

Looking to define the Republican ticket's views on Medicare, the Obama campaign released an online video Monday featuring seniors in Florida talking about how Ryan's proposed changes to the popular health care program could affect them.

"It doesn't make any sense to cut Medicare," says one woman. The video aims to portray the Romney-Ryan ticket as a threat to Medicare and Obama as its protector.

The commercial comes as Romney gently tries to distance himself from his running mate's budget plan, making clear that his ideas rule, not Ryan's.

"I have my budget plan," Romney said, "And that's the budget plan we're going to run on."

He walked a careful line as he campaigned with Ryan, a tea party favorite, by his side in North Carolina and Wisconsin, singling out his running mate's work "to make sure we can save Medicare." But the presidential candidate never said whether he embraced Ryan's austere plan himself.

The pair faced an estimated 10,000 supporters in Wisconsin as Ryan returned Sunday to his home state for the first time in his new role.

"Hi mom," Ryan said, voice crackling as he took the stage and looked out over a sprawling crowd.

An enthusiastic Romney seemed to feed off the energy.

"If you follow the campaign of Barack Obama, he's going to do everything in his power to make this the lowest, meanest, negative campaign in history. We're not going to let that happen. This is going to be a campaign about ideas, about the future of America," Romney said. "Mr. President, take your campaign out of the gutter. Let's talk about the real issues that America faces."

The Romney campaign, meanwhile, released a new ad accusing the Obama administration of "gutting welfare reform."

The new television advertisement released Monday accused the Obama White House of stripping the work requirement from the nation's welfare law. It's the same charge the Republican candidate levied in a separate ad last week.

Independent fact checkers have found the premise of the ad to be false.

___

Online:

Obama video: http://www.youtube.com/watch?vA4OACn0Kkbk