Carly Fiorina has dwindled to near- irrelevance in the Republican primary field, as illustrated by her demotion to the undercard debate. But Fiorina, piping up from the kiddie table Thursday, said something so calculatedly outrageous that it demands response: “Unlike another woman in this race, I actually love spending time with my husband.”

This reference to Hillary Clinton was no gaffe. It was in Fiorina’s opening statement, in response to a question about the economy. In a campaign that has, so far, been blessedly free of sexism toward the Democratic front-runner, this was the most retro, sexist remark yet, at least where Clinton is concerned.

Shame on Fiorina.

I wrote recently that it was fair game for Donald Trump to raise the subject of Bill Clinton’s conduct toward women, when Hillary Clinton had both dispatched her husband as surrogate in chief and attacked Trump’s undisputed “penchant for sexism.”

Any campaign surrogate’s past remarks and behavior are fair game — a former president’s surely are , especially when they stand in contradiction to the candidate’s message. Bill Clinton’s philandering is between him and his wife, not a legitimate topic for campaign commentary. His inappropriate, arguably even predatory, behavior toward women is.

Republican presidential candidate Carly Fiorina went after the only other woman running for president during Fox Business Network's undercard debate on Jan. 14. (Sarah Parnass/The Washington Post)

That distinction explains and underscores why Fiorina’s comment was so out of line. What does she know of the Clintons’ marriage? What does anyone know about another person’s marriage? Fiorina says she loves spending time with her husband, and great for her, but she has no clue — none — about whether Hillary Clinton loves spending time with hers.

For what it’s worth, I believe Clinton deeply loves her husband, which explains her decision to stay with him — a choice that conservatives should applaud, not disdain. But I also believe that how they feel about one another, and how much time they spend together, is none of our business. Just like Trump’s multiple marriages.

In post-debate television appearances, Fiorina flailed around in the muck when called on to justify her remark.

Why hadn’t she questioned the state of other candidates’ marriages, asked Chris Matthews on MSNBC’s “Hardball.” Fiorina: “There’s only two women running for president. I’m one, and Mrs. Clinton is the other.” Um, but other candidates are married, aren’t they? Only the wives are relevant?

On MSNBC’s “Morning Joe” on Friday, Fiorina offered a different non-explanation for raising the subject: “Bill and Hillary Clinton have craved power their entire lives.”

The Huffington Post’s Sam Stein: “Why even go to the point that you’re criticizing her marriage?”

Fiorina: “Well, I guess I would say, you know, if my husband had done some of the things Bill Clinton had done, I would have left him long ago.”

Stein, in a tone of disbelief: “Why is that a campaign issue?”

Fiorina: “Oh, I think if you’re running for the presidency of the United States, everything’s an issue. . . . If you’re going to lead, people have to trust you, and in order to trust you, they have to know you. So, yes, I think it’s all fair game.”

Whoa. It’s one thing for a voter to decide for herself whether to think well or ill of Clinton for staying in her marriage. It’s quite another for a rival candidate to deploy that decision — or in Fiorina’s case, to make smarmy insinuations about the state of the Clinton marriage — against her.

Which brings us to the rampant sexism embedded in Fiorina’s comments. First, she feels empowered by her gender to go after another woman in a way that a male candidate would not. Second, Fiorina chose not to focus on Clinton-as-politician but Clinton-as-wife, an issue irrelevant to her suitability for the presidency.

Finally, her particular critique suggests that Clinton’s marriage is a sham tool in her unseemly — unwomanly? — quest for power. Clinton is, in Fiorina’s depiction, a grasping woman willing to tolerate humiliation in the service of her ambition.

Would Fiorina question the amount of time that a male candidate spends with his wife and family? Of course not. Indeed, unedited video footage posted by Sen. Ted Cruz’s (R-Tex.) campaign includes his wife describing how he once returned home to Texas to his daughter shrieking, “There’s a guest in the house!”

Heidi Cruz: “So even though they know he’s very much a part of our home, they do sometimes see him as a guest.”

To imagine how that would play with a female candidate in the guest- parent role is to recognize the double standard to which female candidates are subjected — including by rivals of their own gender.

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