On Aug. 30, actor and liberal activist Mark Ruffalo was suddenly less “woke” than he’d been the day before.

His crime? He’d signed on to executive produce a film in which the openly gay actor Matt Bomer will play a trans woman. The trans community was outraged: Why had a trans actor not been cast?

“I auditioned for this,” trans actress Jen Richards tweeted. “I told them they shouldn’t have a cis man play a trans woman. They didn’t care.”

Ruffalo, by the way, is on the right side of just about every left-wing issue there is. His Twitter feed streams support for #BlackLivesMatter, the LGBT community, anti-fracking efforts and access to clean water.

To be woke is to be beyond awake to every civil and humanitarian injustice, large or small.

Yet casting Bomer endangered Ruffalo’s wokeness — which is now the ne plus ultra of political correctness.

To be woke is to be beyond awake to every civil and humanitarian injustice, large or small. It is to be aware not just of “white privilege” — another legitimate concept that sounds smugly chic — but of whatever societal, economic, racial privilege you may enjoy, to feel just enough guilt about it and to engage with the world thusly.

“Woke” was added to Dictionary.com this year, along with cisgender (anyone not transgender), misgender (mistaking someone as male or female) and panromantic (someone attracted to all gender identities and orientations). Wokeness is the subject of countless essays and online forums. There are sites where you can buy “woke” merchandise, branded sweatpants and baseball caps. (Sartorially, the Black Panther movement this is not.)

Anyone who thinks they’re woke might want to think again. Are you aware of the Blaxican community? Are you dialed in to intersectionality? Are you fluent in disablist vocabulary?

One misstep may reveal you as the hypocrite you are — at least on social media, where no utterance goes unparsed, no armchair civil-rights advocate unmoved.

Even Erykah Badu, credited with introducing the word and concept in her 2008 song “Master Teacher,” has been criticized for her views on black-on-black crime and the proper skirt length for young girls.

“Wait, what?” said The Root site, naming Badu among the 15 “sleepiest” — aka not woke — black figures of 2016, along with conservative commentator Stacey Dash, Clarence Thomas and Dr. Ben Carson.

Last week, Lena Dunham — ultra-liberal product of St. Ann’s, Oberlin, and two downtown artist parents — was pilloried on social media for an interview she did with Amy Schumer. The two discussed how much they hated going to the Met Gala (Side note: Is no one afraid of Anna Wintour anymore?), and Dunham especially took issue with her tablemate, New York Giants receiver Odell Beckham Jr.

“It was so amazing, because he looked at me and he determined I was not in the shape of a woman by his standards,” Dunham said. “He was like, ‘That’s a marshmallow. That’s a child. That’s a dog.’ I was like, ‘This should be called the Metropolitan Museum of Getting Rejected by Athletes.’ ”

It was a supremely narcissistic comment, one really at her own expense. But in our current climate, Dunham’s observation was elevated — or denigrated, depending on your point of view — to subtextual thought crimes rooted in slavery, lynching, and white female objectification of the black male.

“I would never intentionally contribute to a long and often violent history of the over-sexualization of black male bodies, as well as false accusations by white women towards black men,” she later Instagrammed.

Does anyone really think this is what Lena Dunham meant by her original comments? Does Lena Dunham? Can anyone even tell at this point?

The shaming and blaming over who’s woke, what constitutes woke and who gets to judge is a reminder that no one brutalizes liberals more than other liberals. It’s an old truism that mistakes help us learn, but somehow wokeness decrees that any small misstep, no matter how unintentional, shouldn’t be tolerated. It demands a level of understanding that it won’t extend.

On the flip side are those celebrities who’ve somehow managed to hit peak wokeness as defined by progressives. “Grey’s Anatomy” star Jesse Williams did it with an impassioned speech at this year’s BET awards, which went viral.

San Francisco 49ers quarterback Colin Kaepernick — already a rarity in the NFL, where black quarterbacks have been nearly nonexistent — is another.

Yet the wheel could turn on either of them — as it did on Badu — with just one mistake, one dubious comment. Such is the unforgiving nature of wokeness.

Kaepernick has been kneeling during the national anthem in protest of racial injustice. Other woke athletes have begun to follow, and Kaepernick’s jersey is now the #1 seller in the NFL store.

“I want to thank everyone who has shown me love and support,” Kaepernick Instagrammed.

Kaepernick’s protest is smart in our liberal “Gotcha!” culture for one particular reason — it’s silent. The less he says, the more likely he evades the self-appointed woke police.