Republicans are rejoicing at Mitt Romney’s selection of Paul Ryan as his vice-presidential running mate.

But so are Democrats.

Ryan, a Wisconsin congressman, is the architect of the Ryan budget plan that makes big changes to Medicare and Medicaid and could allow for some privatization of Social Security. And that’s widely seen as a politically risky stance in Florida, a must-win state for Republicans.

Ryan might have another Florida problem: He once opposed the U.S. embargo on Cuba, a now-reversed stance that concerns some in Miami-Dade’s exile community, which is overwhelmingly Republican and had hoped that one of its own, Sen. Marco Rubio, would have been picked as Romney’s running mate. The county’s elderly Cuban population also relies heavily on government assistance, particularly Medicare.

Polls indicate that voters over 50 years old — who make up more than half the Florida electorate — are wary of changes to Medicare, Medicaid and Social Security, which together pump about $96 billion yearly into the hands of the elderly, the infirm and the hospitals, doctors and other providers who give them care.

By picking Ryan, Romney shows he’s ready to fight for conservative changes to the liberal-legacy programs.

Battle of ideas

“We won’t duck the tough issues … we will lead,” Ryan said in his official acceptance speech in Norfolk, Va. “We won’t blame others … we will take responsibility. We won’t replace our founding principles … we will reapply them.”

Democrats are ready, too, for a battle of ideas.

“Paul Ryan wants to privatize Social Security. Looking forward to welcoming Mitt and his pick to Florida,” U.S. Rep. Ted Deutch, a Boca Raton Democrat, tweeted. “There’s nothing brave about cutting the programs that America’s seniors rely on for their health and financial security.”

At the heart of the controversy is Ryan’s proposal to turn Medicare in the future into a “premium support” system that would directly subsidize insurance companies on behalf of seniors. It would essentially put more caps on future Medicare expenditures.

Democrats prefer to use the “V” word to describe the plan: Voucher. And they point to independent studies showing that the voucher, a predetermined amount of money that escalates at a predetermined rate over time, won’t keep pace with the inflation of medical costs.

Bottom line: Seniors would have to pay much more out of pocket in the future. Services could be cut.

Ryan and the plan’s defenders point out that nothing’s free. Someone’s always paying something for Medicare or any other government program. He said he wants to change the plan for those younger than 55 to save the program, which is on an unsustainable path.

A Florida poll last week showed baby boomers, worried about their future, plan to rely more on Social Security and Medicare than they had initially anticipated. So talk of cuts can spook these voters.

Similar to voters overall in other polls, baby boomers in Florida deadlocked 45-46 percent over whether they’d vote for President Barack Obama or Romney, according to an American Association of Retired Person’s survey of 500 older voters last week. Retirees favored Romney over Obama by 48-43 percent, a lead within the poll’s 4.4 percent error margin.