In the debate over the weekend for the Republican presidential candidates, Mitt Romney offered to bet $10,000 on a health care claim, generating all kinds of attention. But just a couple of minutes earlier, Romney made a claim that was far less colorful, but far more dishonest.

As part of a discussion on the Affordable Care Act, Romney told viewers, “Let’s not forget, only one president has ever cut Medicare for seniors in this country, and it’s Barack Obama. We’re gonna remind him of that time and time again.”

Jonathan Cohn, who generally avoids using the “l” word, calls Romney’s claim “a flat-out lie.”

There are a few relevant angles to this. The first is the notion that Obama’s health care law “cuts Medicare.” It’s an inherently dubious claim — as has been explained many times before, “The Affordable Care Act does reduce Medicare spending by $500 billion over the next 10 years. But here’s the catch: Those dollars aren’t taken out of the current budget, they are not actual cuts, and nowhere does the bill actually eliminate any current benefits. The $500 billion is all in future spending reductions and come through the law’s attempts to slow projected growth, not cut spending.”

The second is the notion that “only one president has ever cut Medicare.” Cohn knows better.

During the 1990s, Bill Clinton signed the Balanced Budget Act. That reduced Medicare spending by even more than the Affordable Care Act will.

In the 1980s, first Ronald Reagan and then George H.W. Bush introduced major changes to the way Medicare pays for services: Reagan brought a “prospective payment system” to Medicare hospital insurance while Bush brought a fixed fee schedule to Medicare physician insurance.

I’m actually note sure whether the fee schedule for physicians reduced Medicare spending in the ensuing years, but the new payment system for hospitals certainly did. And both changes were far more socialistic in nature than anything the Affordable Care Act contemplates. The fee schedule, in particular, is effectively a form of price controls.

And then there’s the third problem: Romney made the remarks on Saturday, after endorsing Paul Ryan’s budget plan on Friday. In other words, on Friday, Romney said he supports privatizing Medicare out of existence, replacing it with a voucher scheme. “We’re going to have to make changes like the ones Paul Ryan proposed,” he told voters. Just one day later, Romney nevertheless felt comfortable falsely accusing President Obama of trying to “cut Medicare.”

As we talked about yesterday, this kind of shameless dishonesty may not be as entertaining as Romney’s willingness to bet $10k, but it’s far more important.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.