President Obama's campaign is hoping to scare supporters into opening their wallets ahead of the November elections by casting Rep. Paul Ryan of Wisconsin, Republican Mitt Romney's newly chosen running mate, as a dangerous, right-wing extremist favored by the Tea Party.

"Congressman Ryan is a certifiable right-wing ideologue," top Obama adviser David Axelrod said Monday on "CBS This Morning." "His views are quite harsh."

The demonization of Ryan by the Obama forces began minutes after Romney introduced his VP choice Saturday. By Monday, Axelrod and a half-dozen Obama strategists were blanketing the airwaves and sending fundraising emails to supporters claiming that Romney and Ryan would pursue an extremist agenda if elected to the White House.

"Starting now, we can expect even more wealthy, right-wing ideologues lining up to support the Romney-Ryan ticket," one Obama campaign email said. "If we don't do what we can to keep this close, right now at this crucial moment, we risk letting the other side run away with it."

Ryan, a seven-term congressman, authored House Republicans' budget proposal, which includes steep spending cuts and an overhaul of the Medicare system intended to save money, though Democrats claim it would "end Medicare as we know it."

"I welcome him to the race," Obama said at a campaign stop in Iowa, while Ryan was campaigning in another part of the state. "He's an articulate spokesman for Gov. Romney's vision. But it's a vision that I fundamentally disagree with."

Obama's advisers believe that the addition of Ryan to the Republican ticket creates an opening for the president among senior citizens, who are less receptive to changes Ryan is proposing to Medicare.

The support of the elderly could be particularly helpful to Obama in Florida, a key swing state where seniors account for nearly a fifth of the population.

"It doesn't make any sense to cut Medicare," a Florida woman says in a new online ad the Obama campaign rolled out Monday. Medicare is a boon for senior citizens," says another woman. "And without that, we choose between food and going to a doctor."

With Democrats using Ryan's budget to sharpen their case against Romney, Romney on Sunday politely distanced himself from the proposal, saying: "I have my budget plan. ... And that's the budget that we're going to run on."

Still, the Obama campaign expanded its offensive against Ryan to include his opposition to ending the military's "don't ask, don't tell" ban on gays serving openly in the military. Calling Ryan the "ideological leader of the Republican Party in Congress," Obama blamed him for the congressional gridlock that derailed federal aid to farmers suffering through a drought.

"If you happen to see Congressman Ryan, tell him how important this farm bill is to Iowa and our rural communities," Obama told a farming community in Council Bluffs, Iowa, where he announced his own initiative to aid farmers by having the federal government buy more than $150 million in meat, poultry and fish.

"We've got to put politics aside when it comes to doing the right thing for rural America and for Iowa," Obama said. "What's holding us back right now is Washington politics."