Presumptive Republican nominee Mitt Romney and his newly-named running mate, Wisconsin Rep. Paul Ryan, have made clear that they are doing more than defending their proposed changes to Medicare.

They’re welcoming the debate.

"President Obama is actually damaging Medicare for current seniors. It's irrefutable," Ryan told Fox News in an interview set to air this evening. "And that's why I think this is a debate we want to have, and that's a debate we're going to win."

That's a charge echoed in a new television ad released Tuesday by the Romney campaign, which charges the president with cutting $716 billion from Medicare at the expense of current retirees. (These cuts, which were enacted through health care reform, are largely used to pay for the costs of the new health reform law.)

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Republican presidential candidate Mitt Romney speaks during a campaign rally at American Energy Corportation on August 14 in Beallsville, Ohio.

The Romney campaign's newfound eagerness to engage President Obama on Medicare appears to draw more from Republicans' 2010 playbook than anything else.

But the strategy raises the question: Can it work -- again -- after Republicans passed the Ryan budget plan in 2011 and 2012?

The Romney campaign has gambled that it will.

"You see, when he ran for office he said he’d protect Medicare, but did you know that he has taken $716 billion out of the Medicare trust fund – he’s raided that trust fund – and you know what he did with it? He’s used it to pay for Obamacare – a risky, unproven, federal government takeover of health care," Romney said Tuesday in Ohio. "And if I’m president of the United States we’re putting the $716 billion back."

Going on offense against Obama -- even with a strategy that is now two years old -- might prove to be the best way for Romney to defray the inevitable attacks he invited by adding Ryan, the GOP budget guru, to the ticket.

But arguably the most significant shift in the debate over entitlements during the last two years came in the form of two budgets authored by Ryan in his capacity as chairman of the House Budget Committee. Those proposals call for major changes to Medicare, principally by transforming it into a voucher (or "premium support") program for future retirees who are currently under the age of 55.

"The truth is that the Romney-Ryan budget would end Medicare as we know it: people with Medicare would be left with nothing but a voucher in place of the guaranteed benefits they rely on today," said Obama campaign spokeswoman Lis Smith. "And they do it all to pay for massive tax cuts for millionaires and billionaires – the very same top-down economic scheme that crashed our economy and devastated the middle class in the first place."

Clouding the matter, though, is Romney's apparent disavowal of elements of Ryan's own plan, despite having previously said that he would sign the Ryan budget into law if it were the plan Congress were to send him.

For instance, Ryan's budget proposals leave in place the $716 billion of cuts to Medicare that Romney has vowed to restore.

The presumptive Republican nominee’s campaign has made clear since Saturday, when Romney formally named Ryan as his running mate, that the two budgets authored by Ryan during his time at the budget committee don’t fully represent Romney’s views.

The candidate himself made that much clear on Monday, when he told reporters in Florida that his own plan for Medicare is “very similar” to Ryan’s, though not exactly the same.

“We haven’t gone through piece by piece and said, ‘Oh, here’s a place where there’s a difference,’” he said, explaining that he couldn’t immediately recall an area of explicit difference.

Romney's website saysthat his plan "almost precisely mirrors" a proposal put forward by Ryan and Oregon Sen. Ron Wyden, which would move forward with a premium support plan, but allow future retirees to maintain existing Medicare benefits as an alternative option, but in competition with private plans and with premium levels meant to cover its costs.

But Romney and Ryan, so far, haven't emphasized this alternative, relying instead upon criticizing Obama's own cuts to Medicare.

NBC's Alex Moe contributed

If the bipartisan Congressional committee tasked with reducing long-term federal debt does not agree on a deal by Thanksgiving, it will trigger trillions of dollars in across the board cuts, but the committee is finding it difficult to agree on taxes and entitlements. NBC’s Luke Russert reports.