President Barack Obama wasn't addressing only seniors when he attacked Mitt Romney’s stance on Medicare on Thursday in Florida; he was also focusing on those voters who, he warned, would face a radically different Medicare system if Republican plans were imposed.

At his first event during a two-day trip to Florida, a state where seniors make up 17.3 percent of the population, Obama took aim at Republican proposals to reform Medicare. “Medicare” is a buzzword sure to perk up the ears of the state's retired population, which leans on the program for medical care.

"He plans to turn Medicare into a voucher program. So if that voucher isn't worth enough to buy the health insurance that's on the market, you're out of luck. You're on your own," the president said of Romney’s position. "One independent non-partisan study found that seniors would have to pay nearly $6,400 more for Medicare than they do today."

That particular line of attack is directed at middle-aged voters who will be eligible for Medicare in the next couple of decades. Obama also tied Medicare’s solvency to the current debate over the future of the Bush-era tax cuts.

"It's wrong to ask seniors to pay more for Medicare just so millionaires and billionaires can pay less in taxes," he said. "That's not the way to reduce the deficit."

The focus on Medicare is intentional; Democrats enjoyed a degree of political traction when they first targeted the 2011 budget written by House Budget Committee Chairman Paul Ryan, a Republican from Wisconsin. In May, the Obama campaign released a web video that claimed Romney would end Medicare in its current form and that a typical 65-year-old woman could be left “with nothing but a voucher to buy insurance coverage, which means $6,350 extra per year for a similar plan.”

That attack was premised on Romney's endorsement of the "Path to Prosperity" authored by Ryan -- who is believed to be on Romney’s shortlist for running mate -- for its proposed changes to Medicare.

At the time, Politifact debunked the claims by the Obama campaign, saying they were based only on Ryan's 2011 proposal, and not the subsequent plan he coauthored with Democratic Sen. Ron Wyden of Oregon, one that offers seniors a more traditional Medicare option. And the non-partisan study the president mentioned was the Congressional Budget Office report from April of 2011, which analyzed Ryan’s original budget proposal. 

But the president’s remarks on Medicare do highlight the lack of specifics in Romney’s plan. As long as the presumptive GOP nominee provides only an outline of what he would do to keep the costs of Medicare under control, Obama can continue to campaign on the idea that seniors might very well pay more in the future under a President Romney.

 “Bottom line: There is a clear choice in this election for seniors between President Obama who has been a strong advocate for strengthening Medicare, and Mitt Romney who supports a voucher system that could increase costs," said Obama campaign spokesperson Ben Finkenbinder.

In a statement, Lanhee Chen, Romney's campaign policy director, disagreed, saying that Romney has "a plan to preserve Medicare for today's seniors while strengthening it for future generations." 

Obama, Chen said, would take "hundreds of billions of dollars from Medicare to spend on Obamacare and will leave seniors with fewer choices."

Expect the Obama to continue hitting Romney on Medicare and taxes later Thursday and Friday as he wraps up his trip to Florida with appearances in West Palm Beach, Fort Myers and Orlando.