When politicians at any level are confronted with a controversy, I generally think it’s a mistake to demand they take a polygraph test. The technology is good, but it’s not perfect.

That said, Herman Cain was asked the other day whether he’d be willing to volunteer for a lie-detector test, as part of the scandal surrounding sexual-harassment allegations. The Republican presidential hopeful replied, “Absolutely.”

And while that inspired some confidence in his side of the story, a few seconds later, Cain added, “I’m not going to do that unless I have a good reason,” at which point his credibility was in doubt all over again.

Yesterday, the presidential candidate made matters slightly worse.

Herman Cain, on Neil Cavuto’s “Your World” on Fox News just now, reverted back to blaming the Rick Perry campaign for the emergence of allegations from the 1990s — and turned tables on his accusers.

“When they take a lie detector test, I’ll take a lie detector test!” Cain said of the women, per POLITICO’s Juana Summers.

This guy is clearly presidential material, isn’t he?

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.