Presumptive Republican vice presidential nominee Paul Ryan launched an offensive on President Barack Obama’s cuts to medicare to pay for ObamaCare, his first public reference to the issue since accepting the role as Mitt Romney’s running mate.

“The president took $716 billion from the Medicare program, he raided it, to pay for ObamaCare,” Ryan expained, noting that an Obama aide called the cuts an “achievement” in a television interview…

“Governor Romney and I will protect and strengthen Medicare for our current seniors and for our future seniors of tomorrow,” Ryan added…

“I’m told President Obama is talking about Medicare today, “Ryan said. “We want this debate. We need this debate. And we will win this debate.”

Ryan plans, for the first time, to travel on his own this weekend to senior-heavy Florida, where his campaign has said he will address entitlement reform.

A Ryan campaign aide emailed reporters to say that Ryan would “highlight President Obama’s record of slashing Medicare for current Florida seniors to fund Obamacare.” And a second campaign aide, speaking to reporters in Denver on Tuesday, told reporters that “this is a debate we invite.”

“The message here is that we’re on offense on Medicare,” the aide told reporters. “There’s only one candidate in this race that has raided over $700 billion dollars from Medicare in order to set up a new entitlement that we can’t afford and is making it harder for businesses — especially small businesses — to create jobs.”

Some Republicans worry that fighting about Medicare takes valuable time from talking about jobs, growth and deficits. True, but this fight was coming anyway. Better to debate it now in ways the Romney campaign can control rather than see it raised in the campaign’s final moments through under-the-radar robo calls and mailers to seniors by Democrats.

It is said that in politics, if you’re explaining, you’re losing. That’s not always true. Sometimes when you’re explaining, you’re reassuring voters and undermining your opponent’s credibility.

That’s the case with this issue now. It’s why Team Romney was smart to quickly run an ad attacking Mr. Obama for robbing Medicare to pay for ObamaCare.

Democrats have long had an issue advantage on Medicare. Republicans cowered in fear. This time it’s different. The Romney-Ryan ticket is not only talking about Medicare, it is putting Mr. Obama on the defensive. If Republicans succeed, politics will never be the same.

In the last few days, the Romney campaign has moved to dramatically change the terrain of Medicare politics, and it looks like the Democrats are beginning to realize how vulnerable they might be. Because of Obamacare, it is the Democrats who now plan to cut current seniors’ benefits (especially those in Medicare Advantage) and access to care (thanks to the IPAB) while still failing to avert the program’s (and the nation’s) fiscal collapse, and because Romney would repeal Obamacare and pursue a version of the Ryan-Wyden premium-support reform it is the Republicans who would protect current seniors’ benefits and make them available to future seniors while saving the program from collapse through market reforms. Through the candidates’ statements this week and through this new ad, Romney and Ryan have made clear they’re going to inform voters about this and force the Democrats to defend themselves on Medicare.

That won’t be easy for the Left, since the Romney campaign’s charges are true, and it is beginning to become apparent that the Democrats are totally unprepared for the coming fight. Their defenses so far fall into roughly three categories: Ryan did it too, the Obamacare Medicare cuts aren’t very serious, and finally what can only be called frantic distractions. Even as pure demagoguery (let alone as efforts at actual substantive arguments) all three are exceptionally weak defenses, and suggest the Democrats could be in serious trouble.

Rather than instituting free market reforms, the Democrats are applying governmental infrastructures like the Independent Payment Advisory Board (IPAB). This, they hope, will tame the runaway cost of Medicare, but it also will ruin traditional Medicare for future recipients as well. The program will be fundamentally different in the future than it is today, thanks to the IPAB, which will be unelected and largely free to act without interference from Congress. If the GOP is vulnerable on premium supports, Democrats are at least as vulnerable on the IPAB…

So, where does that leave us? The GOP has proposed a premium support program for the next generation of recipients in the hopes of saving Medicare for the future. Politically dangerous, for sure. But the Democrats have blown past mere danger and charged headfirst into the utterly suicidal: They are using a top-down governmental board to cut costs in ways that will likely diminish the availability of care, not to secure the future of the program but to bankroll a brand new entitlement.

So, who is more vulnerable to “Mediscare” this cycle?

Answer: the Democrats.

There are many Americans who believe two things about where things stand right now: The Romney-Ryan approach is unacceptable, and the status quo is unsustainable. Obama may be able to win the election by persuading a majority of the few voters still open to persuasion that in the short-term, the status quo is preferable to Romney-Ryan. But if he closes the deal by shutting the door to the reforms that we may well need in the long-term, it will be a Pyrrhic victory.

Let me be specific. A number of Democrats once believed—and some still do—that a well-crafted version of premium support is part of a balanced and sustainable long-term fix for Medicare. If the effect of the Ryan choice is to take not only the Ryan budget’s version of premium support off the table, but also the kinds of approaches that Alice Rivlin and Ron Wyden have proposed, then we’ll be left with far less appealing options for stabilizing Medicare.

In a November 2009 interview with ABC News’ Jake Tapper, Obama acknowledged that a third of the funding for ObamaCare came from cutting Medicare…

Tapper went on to ask Obama whether he would allow Congress to repeal or patch the Medicare cuts as it does every year with the so-called Doc Fix, a measure designed to ensure adequate reimbursement payments are maintained to doctors who care for patients covered by Medicare.

Obama said that his Medicare cuts were permanent and that he would never allow Congress to repeal them.

“I think the Democrats are discovering that they stepped on a land mine with Medicare.”