The Romney and Obama camapigns are again trading blows over Medicare this morning. The Obama campaign is up with a new ad that hits back at the Romney campaign attacks, defending Obamacare for protecting Medicare against fraud and waste and strengthening benefits, while pointing out that the Ryan plan would weaken the program and drive seniors’s costs up. Meanwhile, the Romney campaign is out with a new memo claiming that their message — that Obama “raided” Medicare to pay for Obamacare — has given them momentum.

It’s important, though, to get at the true nature of the Romney strategy here. It isn’t about drawing an actual policy contrast with the Obama campaign. It’s about obfuscating the actual policy differences between the two candidates over the program.

The claim that Obama has “raided” old folks’ Medicare to pay for Obamacare is absurd on its face, since Paul Ryan’s budget contained the same savings, and those savings are wrung from providers, not basic benefits. Some of those savings pay for expanded benefits under the health law. By contrast, the Romney-Ryan plan — by repealing Obamacare and transforming Medicare into a quasi-voucher program — probably would drive costs up for seniors. Obama says we can control Medicare costs without transforming its basic mission; Obamacare is a first step in that direction. Meanwhile, Romney and Ryan are committed (for seemingly ideological reasons, in Ryan’s case) to changing Medicare’s core mission, and insist this is the only way to make it fiscally sustainable over the long haul — even as they are proposing deep tax cuts that disproportionately benefit the rich.

The Romey “Obama raided Medicare” strategy is all about muddying the waters so voters don’t understand these basic policy and ideological differences. Eugene Robinson explains:

The Romney campaign knows that as long as people are trying to sort out the facts of this specific allegation, they aren’t talking about the real differences between the two parties on the very nature of entitlement programs such as Medicare...

Everyone agrees that something has to be done about skyrocketing costs for Medicare and Medicaid, the health-care program for the poor. Obama took the first step toward “bending the curve” of cost increases with the Affordable Care Act. Leave aside, for the moment, the fact that Romney now pledges to undo the progress Obama has made. The question is what do we want Medicare to be?

There is no reason Medicare cannot be reformed as social insurance. Other industrialized countries provide universal health coverage for their entire populations for a fraction of what we spend in the United States, and those other countries achieve equal or better health outcomes. Surely we can continue to do so for those of retirement age — if we still want to.

The difference is not over whether to do something about Medicare over the long haul; it’s over how to do it. The true nature of this difference is what Romney’s strategy is designed to obscure.

* Obama camp ratchets up pressure over tax returns: Obama campaign manager Jim Messina writes a letter to Romney counterpart Matt Rhoades, making an offer designed mostly for media consumption:

If the Governor will release five years of returns, I commit in turn that we will not criticize him for not releasing more — neither in ads nor in other public communications or commentary for the rest of the campaign.

The Obama camp, obviously, does not expect this offer to be accepted. The idea is to undercut the Romney camp’s pushback — that no matter how much he releases, critics will only demand more — while simultaneously making Obama’s demand seem reasonable (we’re only asking for five years!) and highlighting just how little information Romney has actually released.

Yesterday Romney insisted he has paid 13 percent in taxes for at least 10 years, but still won’t release the returns to prove it, doubling down on his “just trust me” strategy. This letter will keep the story going today.

* Obama turns clock back on Guantanamo: Today, there will be hearings over new administration rules that would further restrict lawyers’ access to detainees, and Baher Azmy of the Center for Constitutional Rights sums up the grim truth about Obama’s larger record:

Torture was President Bush’s legacy at Guantanamo. I hope that President Obama’s legacy will not be that he legitimized indefinite detention without charge and made Guantanamo a place where the United States sends Muslim detainees to grow old and die.

Congress no doubt bears a large part of the blame here, but there’s no escaping the fact that Obama has completely failed to live up to his own promises and rhetoric on this front.

* A big Ryan bump? The Romney campaign’s new memo this moring also argues that the Ryan pick has given the campaign a big bump, as evidenced by tracking polls showing the GOP ticket leading nationally and swing state polls showing him gaining ground.

However, Nate Silver does a deep dive into recent polling and finds that, if anything, the Ryan bump was small by historical standards.

* Paul Ryan, deficit hawk? Michael Linden at the Center for American Progress asks: If Ryan is so good on the deficit, then why did he vote for so much budget-busting legislation passed during the Bush years? Ryan’s own budget won’t tell us in any meaningful detail how it would reduce the deficit, but that aside, Linden notes, he has an actual record of voting to increase federal spending without paying for it.

* GOP insists they can win down ticket on Medicare: Republicans say they are very bullish on their chances of transforming the battle over Medicare in down-ticket races into one over Obamacare, but as Sam Baker notes, this is a claim Republicans have made for years now, and Ryan is an “imperfect messenger” on the issue who risks making it all about Medicare again.

* But Dems relish fight over Ryan: Dem messaging chief Chuck Schumer urges Dem Senate candidates to press on Medicare and Ryan as hard a s possible:

“We know these messages are powerful and cause independents to abandon Republicans. As familiar as these points may seem by now, we must keep repeating them — for two reasons. First, many general election voters are only now turning their attention to the particulars of the political debate. Second, since choosing Ryan, Romney is rather absurdly seeking to distance himself from the most controversial aspects of Ryan’s plan. We must do our part to make Romney own the Ryan plan in its entirety.”

* Is Romney losing the week? Michael Falcone lays it out: As long as Romney is talking about his tax returns and Medicare, and not the economy, he’s losing.

* And let’s document Ryan’s flip flops: The Los Angeles Times has a good rundown on all of them, from the Medicare savings in his own budget to China currency ma­nipu­la­tion to stimulus funds for his own district. But he’s Very Serious!

What else?