THIS POST HAS BEEN UPDATED AS OF 2:38p.m.

Here's a Fix rule for politicians.  Never, ever, ever comment on someone else's personal appearance. Nothing good can ever come of it.

Retiring Iowa Sen. Tom Harkin just broke this rule into a million pieces. Here's what he said about state Senator Joni Ernst, the Republican nominee running to replace him, courtesy of Buzzfeed:

In this Senate race, I’ve been watching some of these ads. And there’s sort of this sense that. Well, I hear so much about Joni Ernst. She is really attractive, and she sounds nice. Well, I got to thinking about that. I don’t care if she’s as good looking as Taylor Swift or as nice as Mr. Rogers, but if she votes like Michele Bachmann, she’s wrong for the state of Iowa.

If you watch the video, what Harkin said isn't just him riffing and going off script.  Nope, he has clearly given some forethought to what he said and doesn't think it's sexist or problematic. He likes the line.  He thinks it's cute and clever and the audience seems at least slightly amused.

Ernst, a National Guard lieutenant colonel who served in Iraq, was not. In an interview with Fox News she said she was "very offended that Sen. Harkin would say that."

"I think it's unfortunate that he and many of their party believe that you can't be a real woman if you're conservative and you're female," Ernst said, adding that there is a double standard in terms of coverage. "I believe if my name had been John Ernst attached to my resume, Sen. Harkin would not have said those things."

She is exactly right.  The relative attractiveness of "John Ernst" would not likely be a focus for Harkin.

Give Ernst credit. She came up with this zinger of a retort to Harkin.

Update #1: Harkin has, so far, declined to apologize.

Update #2: Harkin has now apologized.