ORLANDO, Fla. -- President Obama will let Medicare go belly up.

That is the warning GOP vice presidential nominee Paul Ryan delivered to Florida's seniors Saturday -- a voting bloc that could determine not only the outcome of the Sunshine State but also the election.

"Mitt Romney and I have looked at the issue, worked with Democrats, come up with the best ideas from both parties for a plan to save Medicare," Ryan said during a town hall meeting in Orlando. "President Obama hasn't done a thing. President Obama is obviously complicit with this program going bankrupt."

It's the latest accusation in a perpetual back-and-forth on the issue. For weeks the Romney-Ryan team has been arguing that Obama "robbed" Medicare of $716 billion to pay for ObamaCare.

The Obama campaign says that's false and counters by claiming the Republican ticket is proposing a "voucher" program that would force seniors to shell out $6,400 a year.