It happens without fail: Put Hillary Clinton on a stage, and someone — usually many someones — will ignore what she says to criticize the way she says it.

She’s not smiling enough. She’s shouting. She’s being too "tame." Her voice is "shrill" and unattractive.

It happens even when the other politician on stage is Donald J. Trump.

After the two candidates appeared at NBC’s candidate forum on Wednesday for the first time as opponents in the 2016 presidential election back to back, Reince Priebus noted that Clinton hadn’t smiled enough and had been too "angry" for his personal taste.

@HillaryClinton was angry + defensive the entire time - no smile and uncomfortable - upset that she was caught wrongly sending our secrets. — Reince Priebus (@Reince) September 8, 2016

In fairness, Priebus’s reasoning is motivated — it’s not like he wouldn’t have tweeted something critical of his party’s opponent. At the same time, he was just voicing a criticism that plenty of people (mostly men) have had of Clinton for her entire presidential campaign, and her entire political career. He was simply springing a trap that’s been set for any woman who dares to lead: She has to have gravitas, but she can’t be a bitch. She has to be a leader, but she can’t come across as overly threatening or pushy.

She has to meet two sets of expectations that are often diametrically opposed. This isn’t just a double standard — it’s a metaphysical impossibility.

That’s never been clearer than it is this cycle. In Donald Trump, Clinton faces an opponent who also struggles to meet the expectations of "statesmanship" — and occasionally even gets called out on them. But while Trump gets held to about half a standard, Clinton continues to be held to two. Both are asked to prove their leadership, but only one is asked to prove her humanity.

What would happen if we judged Donald Trump the way we judged Hillary Clinton?

For most of her career, Hillary Clinton’s been measured in comparison to men. She is less warm and authentic than her husband Bill Clinton or her 2016 opponent Bernie Sanders; she is less eloquent and transcendent than her 2008 opponent Barack Obama.

But in what way, precisely, is Hillary Clinton "less" than Donald Trump?

Donald Trump isn’t warm. He rarely smiles; his demeanor tends to exist on a continuum between "gruff" and "smug."

He nearly never laughs. Gawker attempted to track down footage of Trump laughing; it found only one video from February 2016, in which he reacted to a clip of Hillary Clinton barking like a dog during a speech. (Clinton literally had to do a dumb animal impression to get Trump to laugh.) He didn’t laugh during his entire Comedy Central roast in 2011 — despite the fact that comedians had been told in advance which things were acceptable to joke about. And when the 2011 White House Correspondents’ Dinner turned into an unofficial roast of Trump, he took it so seriously that he became resolved to run in 2016.

The ability to laugh at oneself is one of the things that politicians are expected to do, at least a little, to prove they’re human. To prove they’re people who "voters" (a construct in its own right, usually defined as "white middle-class suburban Americans) both trust to make decisions in the War Room and think they could hang with in the living room.

He’s not uplifting. His nomination speech took the darkest, angriest campaign speech in modern presidential history and made it darker and angrier. His attempt at an uplifting, unifying message got buried in two consecutive speeches by his vitriol; the campaign ultimately had to post it on its own as a Facebook note for the press to notice it.

He doesn’t connect with the public. Trump is often described as a good listener in private — but in public, he’s as condescending to his allies and followers as he is to his enemies.

During the NBC forum, Trump interrupted a veteran to correct her about the number of military suicides a day — except that her number was correct and his was wrong.

Trump still brags about beating his primary opponents. A statesman is expected to be humbled by tragedy; Trump’s response to tragedy, from terrorist attacks to gun deaths in Chicago, is to brag that he predicted it. The list goes on.

If you actually subject Donald Trump to the same scrutiny Clinton receives, you’ll see that he doesn’t show any of the qualities that other politicians — and especially female politicians — are criticized for lacking.

Clinton is expected to embody both "leadership" and "femininity" — which we perceive as opposites

It’s always easier to see social roles and expectations when someone fails to live up to them. Trump’s failure to have the "temperament of a leader" — something for which he actually does get called out, by the media and members of his own party — shows what sort of expectations of a "leader" people have.

By that token, though, Hillary Clinton — or rather, criticisms of Hillary Clinton — have long illuminated the expectations that are set for women leaders. And she (or rather, the criticisms of her) have shown that women in power are expected to fill two opposing roles at once.

On one hand, the leader: statesmanlike (ahem), commanding, well-spoken, imbued with gravitas. On the other hand, the woman: gracious, warm, yielding, a good listener.

Something analogous is true of male politicians: They’re expected to be both leaders and humans, to be "relatable" at all times. But there’s a lot of overlap between those two constructs. Bill Clinton’s ability to "feel your pain" didn’t make him less of a statesman.

Femininity and political leadership, on the other hand, have been defined in opposition to each other for literally the entire span of Western history — as historian Mary Beard points out, men telling women "that their voice was not to be heard in public" goes all the way back to The Odyssey.

Of course, people who believe in contradictory stereotypes rarely understand they’re contradictory. In practice, any Clinton critic only criticizes her from one side at a time: for not being strong enough (for being too yielding and compromising) or for being too strong (too serious, too shrill, interrupting and yelling too much).

In Clinton’s case, she’s usually criticized openly for being an inadequate woman. She is told to talk less and smile more. That can often obscure the fact that she is still expected to be an adequate leader — that she wouldn’t have been able to put together a successful presidential campaign at all (much less her well-regarded tenures as senator and secretary of state) if she had been seen as too conventionally feminine. She wouldn’t have been able to succeed as a woman in public life at all.

Clinton herself acknowledged this, in an interview with the Facebook page Humans of New York: "I know that I can be perceived as aloof or cold or unemotional. But I had to learn as a young woman to control my emotions."

"I was taking a law school admissions test in a big classroom at Harvard. My friend and I were some of the only women... Posted by Humans of New York on Thursday, September 8, 2016

Everybody knows the game is a game, that how a politician comes off is a matter of practice, and that "But will it help her with voters?" is a totally different conversation from "Will it help her run the country?" But the politician is expected to make it all look natural anyway: to evoke leadership and (conventionally gendered) humanity without appearing to try.

And Clinton is put in the absurd position of having to apologize when she fails to project both leadership and warmth at once.

Call it no-politics politics: the no-makeup makeup of public life. If she doesn’t work hard enough to stay in both lanes at once, she’s called defensive and unprepared; if she works too hard, she’s fake and overly polished.

Clinton has decades of experience trying, failing, and trying again to live up to both of those expectations — as impossible as it is to be not only a human leader but a womanly one. Donald Trump is occasionally measured against the expectation of leadership, and found wanting. But he’s given a pass on basic humanity.

No one ever tells Donald Trump to smile.

Understanding how Hillary Clinton would govern