By selecting U.S. Rep. Paul Ryan, R-Wis., to be his running mate, Mitt Romney has also elevated Ryan's plan to reform Medicare, putting in play elderly voters who are skeptical of attempts to reform the cherished senior citizen health care program.

The Obama campaign has already pounced, issuing a press release with the now well-worn admonishment that Ryan's proposal would end Medicare as we know it. Ryan's plan relies on an approach known as competitive bidding that would give future retirees a choice between enrolling in Medicare or receiving vouchers they could use toward purchasing private insurance plans. It would also gradually raise the eligibilty age from 65 to 67.

Critics deride the proposal by saying it will burden seniors with higher costs, undercutting Medicare's promise of comprehensive coverage. Democrats successfully tied Republican congressional hopeful Jane Corwin to the plan during a May 2011 special election in upstate New York, helping Democrat Jane Corwin register an upset victory.

Seniors Overwhelmingly Oppose Ryan's Medicare Proposal

Further, poll after poll has found clear opposition to Ryan's plan, especially to raising the eligibility age. The rejection was particularly pronounced among senior citizens, with a June 2011 survey by the Pew Research Center finding that voters 51 and older opposed Ryan's plan by a margin of 51 percent to 29 percent. Those who disliked the plan were far more likely to feel strongly than those who approved of it.

However, that generational dynamic also produces some mixed reactions: The Pew Survey also found that the bloc of voters ages 66 to 83 was the only one where a majority felt Medicare only needed minor tweaks; in every other age group, a majority of voters said an overhaul was needed. Most Baby Boomers (age 57-65) ranked Medicare as fair or poor, and 61 percent favored allowing people to purchase private health insurance with Medicare dollars.

But attempting to control Medicare costs remains a volatile issue no matter which party is approaching it or how. A March 2011 Wall Street Journal/NBC News poll found that voters across all age demographics are deeply opposed to substantially cutting popular entitlement programs like Medicare and Social Security.

Views on Medicare aren't as tied specifically to a party stamp as they are to an individual's views of the program itself, said Julia Clark, a pollster for Ipsos. When one party is announcing certain things and another is announcing different things, you'll get some fundamental knee-jerk reactions based on party support, but when you isolate the proposed changes or tenets, there's not as much divergence of opinion.

When President Barack Obama sought to address spiraling Medicare costs via his health care overhaul, Republicans exploited concerns over the implications to help fuel a landslide victory in the 2010 mid-term election. Older voters tend to vote in far greater numbers than younger ones, and Americans over the age of 65 supported Republicans by a 21-point margin in 2010.

Romney has continued to pummel Obama over the Affordable Care Act's cost-control measures, asserting shortly after the U.S. Supreme Court upheld the bill that it cuts Medicare spending by approximately $500 billion. (Rather than slash the benefits that flow to seniors, the legislation tries to find savings mostly by reducing payments to health care providers, in part through the creation of an Independent Payment Advisory Board.)

The presumptive Republican nominee has kept it up since announcing his pick of running mate Ryan, telling a crowd in St. Augustine, Fla., on Monday that he would preserve and protect Medicare and saying that Obama's blueprint was not the right answer.

Of course, the question of what constitutes the right answer to Medicare's mounting costs is an open one and is unlikely to be resolved any time soon. But expect a steady barrage of advertisements from both the Romney and Obama camps as they both seek to convince worried older voters that their opponent will devastate Medicare.