An instant mythology has attached itself to Mitt Romney’s selection of Paul Ryan as a running mate: the Wisconsin congressman’s “boldness” and “seriousness” have fundamentally reshaped a race that had previously been mired in the gutter.

Is this true?

Count me as less than persuaded.

If anything has scrambled the politics of Medicare this month, it has been the Romney-Ryan campaign’s promise to restore $716 billion that the Obama administration cut from Medicare to pay for Obamacare — this while exempting those over 55 years old from its own plan to cut Medicare spending. “Medicare jujitsu,” is how Yuval Levin describes the strategy in the Weekly Standard.

But couldn’t Romney have employed the $716 billion wedge no matter whom he chose as his running mate?

Over at National Review, Levin gets this:

It would be easy to attribute the Romney campaign’s firm push for their candidate’s Medicare reform (and assertive attack on the administration’s raid of the program to pay for Obamacare) to his choice of a running mate. But the bold pre-emptive strike we’ve seen this week, which looks likely to seriously blunt the Mediscare offensive the Democrats were hoping for in the fall, seems to be at least as much Romney as Ryan.

I would argue it’s all Romney.

It’s true that the choice of Ryan may have compelled Romney and his advisers to formulate a plan to insulate the campaign from a “Mediscare offensive” with a “pre-emptive strike.” But that’s incidental to the Ryan selection; the Romney campaign could conceivably gotten just as much mileage out of the issue if Sen. Rob Portman or Gen. David Petraeus or whoever were on the ticket.

What’s dispiriting about all this is to see someone like Levin, whom I regard highly, regurgitate campaign rhetoric like “Mediscare offensive” and “the administration’s raid” with a straight face. What is Romney’s “pre-emptive strike” if not a “Mediscare offensive”?

The truth is, both sides are cutting (or slowing the growth of) Medicare by an equal amount.

As Pete Spiliakos wrote shortly after the selection of Ryan was announced:

As between the most recent Ryan budget and the most recent Obama budget, there isn’t any disagreement about whether to cut Medicare.  There isn’t even any disagreement about how much to cut Medicare.  They both agree to fund Medicare at GDP+.5%.  They disagree on how to cut Medicare.

And both sides are “raiding” Medicare to pay for other priorities.

While Obama is raiding Medicare to pay for the Affordable Care Act, Romney are Ryan are proposing to raid it (to the tune of three times as much as Obama’s $716 billion) to pay for tax cuts and more defense spending. They won’t come out and say this, of course — but the numbers simply don’t add up otherwise.

Right now, Romney boosters like Levin are chortling over the political difficulty Obama faces as a consequence of having paid for new spending rather than finance it through deficits. And they’re celebrating an utterly fantastical long-range budget plan that has no prayer of becoming law.

Like I said — dispiriting.