The Service Employees International Union is going after Mitt Romney and two freshman House Republicans on Medicare, with a flight of ads airing in three states.

The union plans to make health care a central theme in its ads this fall. "You're going to see a lot of stuff on Medicare, Medicaid and the Affordable Care Act in multiple races," said SEIU spokesman Mark McCullough.

In Florida, a new statewide radio ad blasts Romney and VP nominee Paul Ryan for their Medicare plan. In it, a nervous-sounding mother calls her son asking about Medicare and the GOP ticket, confused by TV ads on the topic.

"Well, the Romney-Ryan plan does essentially end Medicare, that's what the Wall Street Journal said," her son explains. "What I read said seniors would wind up paying over $6,000 more per year." (That figure applies to Ryan's 2011 Medicare proposal, which he has since revised.)

"I don't like the sound of that," the mother says. When her son in the ad notes that Ryan's plan would cut Medicaid spending, and that Medicaid provides nursing-home benefits, she replies, "Boy, that's scary."

SEIU will spend $322,000 airing the ad, its second radio spot focusing on health care in Florida.

A TV ad in Michigan's 1st Congressional District attacks freshman GOP Rep. Dan Benishek, who is facing a challenge from Democrat Gary McDowell, suggesting his vote for Ryan's budget violated his professional ethics as a doctor. SEIU will spend $152,000 airing it.

Another ad in Virginia's 2nd Congressional District hits freshman Rep. Scott Rigell, who faces a challenge from Democrat Paul Hirschbiel. The ad accuses Rigell of wanting to raise the retirement age and, again, hiking out-of-pocket health-care costs for older Americans. SEIU will spend $126,000 airing it.

SEIU's Medicare attacks focus on Ryan's 2011 Medicare plan, which is different from what Mitt Romney has endorsed. Democrats have largely trained their fire on Ryan's more controversial version.

Using Congressional Budget Office analysis of Ryan's 2011 Medicare plan, SEIU claims the GOP ticket would hike out-of-pocket costs for older Americans by $6,400. Romney has loosely backed Ryan's 2012 plan, which included some significant changes, including a fee-for-service Medicare plan that would "compete" with private insurers on a new Medicare exchange. The Wall Street Journal (mentioned in the radio ad) has called the $6,400 claim faulty, as has The Washington Post's Ezra Klein. The radio ad does not mention that Ryan's reforms would overhaul Medicare for future seniors but not current ones, such as the character in the ad.

The most recent ABC/Washington Post poll showed President Obama with a narrow advantage - 47 percent to 44 percent - on whether he or Romney would "do a better job handling health-care policy." On Medicare, Obama's advantage was 48 percent to 43 percent. SEIU hopes to capitalize on that advantage in its ads.

"At a time when America's workers are moving forward and trying to build their retirement saving lost during a recession caused by Wall Street's excesses, Mitt Romney, Paul Ryan and Congressional Republicans support legislation that would leave Americans facing increased costs, decreased coverage or loss of coverage altogether," SEIU political director Brandon Davis said.