The Fox News campaign to defend Mitt Romney's debate dishonesty reached its logical extreme as contributor Kirsten Powers criticized Obama's camp for crossing an imaginary line forbidding campaigns from accusing their opponents of lying. Never mind that it's a line Mitt Romney himself crossed before he had any evidence to support it.

Romney has been criticized for numerous dishonest and misleading claims he made during the October 3 presidential debate. His statements earned several "false" and "mostly false" ratings from PolitiFact. After the debate, Romney adviser Eric Fehrnstrom even admitted that people with pre-existing conditions may be unable to find health insurance coverage under Romney's plan, contrary to what the presidential aspirant said during the debate.

Yet when Powers appeared on Fox's America Live to discuss the aftermath of the debate, she criticized the Obama campaign for focusing on Romney's actual dishonesty, claiming: “There are a few lines in politics that usually aren't crossed, and one of them is people usually actually don't call other people liars.”

So how does Powers account for Romney's statements leading up to the debate essentially warning that Obama would use the forum to lie?

In contrast to the Obama campaign, which has identified actual false claims made by the GOP nominee, Romney weighed in weeks before a single word was uttered at the debate to suggest that Obama would be dishonest:

“The challenge that I'll have in the debate is that the president tends to, how shall I say it, to say things that aren't true,” Romney told ABC News recently. “I've looked at prior debates. And in that kind of case, it's difficult to say, 'Well, am I going to spend my time correcting things that aren't quite accurate? Or am I going to spend my time talking about the things I want to talk about?' ”

During the very debate Powers discussed, Romney compared the president to a dishonest child:

ROMNEY: I will not reduce the share paid by high-income individuals. I know that you and your running mate keep saying that and I know it's a popular thing to say with a lot of people, but it's just not the case. Look, I've got five boys. I'm used to people saying something that's not always true, but just keep on repeating it and ultimately hoping I'll believe it. But that -- that is not the case. All right? I will not reduce the taxes paid by high-income Americans.

Perhaps it's only OK to call your opponent a liar when you don't have evidence to back up the charge.