But the far more dishonest statement is Boehner’s line that the debt ceiling amounts to a “blank check.” This is a straight-up lie. Not the everyday, casual fudging that politicians do, but a straight up lie. As the Government Accountability Office explains: “The debt limit does not control or limit the ability of the federal government to run deficits or incur obligations. Rather, it is a limit on the ability to pay obligations already incurred.”

This isn’t a perfect metaphor, but not raising the debt ceiling is more like refusing to pay your credit card bill than it is akin to asking for a blank check. Congress appropriates funds; if they don’t want Obama to spend more, it’s within Congress’s power to withhold that money. That’s you know, in the Constitution. I believe the GOP insisted on it being read at the beginning of the 112th Congress, but they don’t seem to have been paying attention.

The Washington Post’s Plum Line was back on the case Thursday, this time with Greg Sargent pointing out that the “blank check line” was not only false, but that Michele Bachmann—who used the line as recently as yesterday—argued against it herself when she got Boehner’s talking point tangled up in her own bag of rhetorical tricks. She was speaking on CNN, several steps ahead of reality. Here’s an account from CNN’s web site:

Republican presidential candidate Michele Bachmann said President Obama would be a “dictator” if he raised the debt ceiling by executive order, using the 14th amendment of the U.S. Constitution as justification.

“It’s Congress that does the spending. The president is prohibited to do that. If he had the power to do that he would effectively be a dictator,” the Minnesota Congresswoman said Thursday on CNN’s “American Morning.” “There would be no reason for Congress to even come to Washington, D.C. He would be making the spending decisions … Clearly that’s unconstitutional.”

Sargent’s response:

Of course, if Congress ultimately determines spending—which of course it does—there’s no way raising the debt ceiling would constitute giving President Obama a “blank check,” as John Boehner and other Republicans keep falsely insisting.

The Plum Line was not totally alone its effort to take Boehner to task over his wildly misleading use of “blank check.” Kudos also goes to The New Republic’s Jonathan Chait and particularly Mother Jones’s David Corn, who two days ago (and two days before us), not only called out Boehner, but also the media for breathing life into the “blank check” lie and making it all the more poisonous.

The GOP is peddling a potent lie. And Boehner and his comrades are able to get away with it because within the current political-media culture there is not much of a penalty for exploiting lies. Reporters toiling for supposedly objective outlets tend to focus on charge and countercharge. (He said it was a lie; he replied that it was not a lie.) Sure, there are fact-checking outfits run by the mainstream media. (I’ve yet to see one pronounce a verdict on the “blank check” charge.) But usually their disapproval does little to stop a politician from repeating a falsehood.

It’s irresponsible when politicians make these claims, but its many times more so when the media so blithely lets them.

Erika Fry is a former assistant editor at CJR.