Honest question: When is defining a woman by her gender sexist? And when can you clearly say that something bad is happening to you because you're a woman (or man)?

Turns out, sexism is a slippery concept to define. And, in a moment when the president of the United States makes comments that sound overtly sexist, it's worth spending a moment trying to understand why it's so hard to pin down.

Case study one: Rush Limbaugh. On his radio show Tuesday, here's how he framed the demise of an ill-fated Obamacare repeal deal in the Senate:

“These three female leftists in the Republican caucus are running the Senate, not Mitch McConnell. Mitch McConnell is not running the Senate. These three women are running the Senate. The conservative Republicans in the Senate are not running the Senate. Three liberal women who call themselves Republican are running the Senate.”

Limbaugh in 2010. (Brian Jones/AP/Las Vegas News Bureau)

Would the political meaning of that paragraph have been lost without the words “female” and “women”? Probably not. By bringing up, over and over, that these “no” votes are women, Limbaugh appears to be signaling that these senators are making policy decisions because of their gender, for which there is no evidence.

It's not unlike how then-candidate Donald Trump said a federal judge couldn't rule fairly on a Trump University case because he's of Hispanic descent.

So can we definitely say that what Limbaugh said is sexist (or what Trump said is racist)? Kelly Dittmar, an assistant professor of political science at Rutgers University at Camden just finished a study on the role of gender in the presidential campaign and said it's tough to answer that question. Maybe. Maybe not. To do so requires a lot of assumptions about intent.

“Is the person weighing the attack doing it purposefully with gender in mind?” she said. Like, would Limbaugh have described three senators who bombed Obamacare repeal by their gender if they were men? It's hard to tell.

Context is a critical indicator. Both men — Trump and Limbaugh — have a history of saying demeaning things to and about women.

In fact, it's impossible to talk sexism without bringing in the president, whose behavior toward women is the umbrella under which all of this is happening. He routinely tries to diminish women who challenge him into a bag of emotions and vanity. (Most recently, he reduced a powerful and influential MSNBC TV show host who criticized him to remarking on her “face-lift.” Weeks later, he greeted the first lady of France this way:

Trump gets a lot of attention for things he says about women. But when President Barack Obama described now-Sen. Kamala D. Harris (D-Calif.) as “the best looking attorney general,” Dittmar pointed out that, yes, people thought that was a bad thing to say. But there was no prevailing view the president was a misogynist, predominantly because Obama doesn't have a history of saying stuff like that.

(Further complicating the “What is sexism?” question is research that draws a distinction between ambivalent and hostile sexism.)

Okay. So there's no clear line that says “yes, this is sexism,” when a man says something about a woman. Is there a clear demarcation for a woman to cry sexism?

Something Jane Sanders said recently caught my eye.

A federal investigation into a land deal she maneuvered as president of a now-defunct Vermont liberal arts college is heating up. Sanders, who is married to Sen. Bernie Sanders (I-Vt.), has denied any wrongdoing. As part of her defense, Sanders told the Boston Globe this: “I find it incredibly sexist that basically [plaintiff Brady Toensing is] going after my husband by destroying my reputation, and that's not okay.”

Sen. Sanders and his wife, Jane Sanders, in Las Vegas in 2015. (David Becker/Reuters)

Republicans immediately seized on that. “Sexist??" a news release from the Republican National Committee read. “Jane Sanders must think Hillary Clinton's campaign was sexist for viewing the alleged bank fraud as a major issue, too.”

Dittmar said it's not immediately clear what Sanders means by throwing out the “s” word. Is she being treated differently by the FBI because she's a woman? The wife of a popular politician?

And I wonder: If there is no clear definition of sexism, does Sanders risk crying wolf, making it more difficult for her (or women in general) to point out overt sexism?

A clearer example of sexism came from Trump adviser Kellyanne Conway, who spoke at a conservative evangelical summit in Iowa over the weekend and criticized her, well, critics for focusing on her appearance rather than what she says. “So much of the criticism of me is so gender-based,” she said, explaining she often feels reduced to “how I look or what I wear or how I speak.”

And perhaps the primo example of a woman crying gender-based foul is Hillary Clinton, who after her loss, blamed, among other things, misogyny. Research suggests she could be right: Voters' perceptions about women in politics are different from what they are about men.

But we come back to the question of intent. If any voters voted for Trump because Clinton didn't live up to their expectation of being a woman, were they even aware they were doing it? If they weren't, was it sexist?

I know, my head hurts, too.

So I'll end with this, a tool Dittmar shared to measure a subject that seems very pertinent these days: When someone says something's sexist, ask them to explain why. Then decides if that sits with you.