Emma Sulkowicz graduated from Columbia College last week, lugging her mattress under one arm as she reached for her degree with the other.

Some classmates cheered Sulkowicz — the self-proclaimed poster woman for the fight against sexual assault — for carrying around the mattress on which she was allegedly raped.

Never mind that her charges against a male classmate couldn’t stick, even under Columbia’s kangaroo-court standards. New York’s Democrats are embracing Sulkowicz and her cause.

Gov. Andrew Cuomo is pushing for passage of what he calls “the toughest law in the nation” against campus sexual violence.

It would make campuses in New York a hostile environment for young men. One misstep and they could find themselves accused of “sexual assault,” denied a fair hearing, expelled and unemployable.

The law would apply at all private colleges in the state, extending regulations that Cuomo has already imposed on the state university system.

Everyone should want to prevent rape. But Cuomo’s bill criminalizes normal sexual interactions.

The bill requires “affirmative consent” at each step of the way when two students have sexual contact. Amazingly, that means punishing students who fail to ask “May I unbutton your blouse?” and “May I kiss you?” and wait for the answer. On May 20, Cuomo said there has to be “clear, unambiguous and voluntary agreement” before any “specific sexual activity.”

Here’s a “sexual misconduct scenario” Yale University drafted to show students how it’s supposed to work:

“Morgan and Kai are friends who begin dancing and kissing at a party. They are both drunk although not to the point of incapacitation. Together they decide to go to Kai’s room. They undress each other and begin touching each other. Morgan moves as if to engage in oral sex and looks up at Kai questioningly. Kai nods in agreement and Morgan proceeds. Subsequently, without pausing to check for further agreement, Kai begins to perform oral sex on Morgan. Morgan lies still for a few minutes then moves away, saying it is late and they should sleep.”

Did you notice any assault? Probably not. But according to Yale, Kai would be guilty of sexual assault and reprimanded, marring his college record.

Affirmative consent is dangerous enough, but Cuomo would also deny accused students due process. What goes on in a dark dorm room is usually one student’s word against another’s.

Cuomo’s bill officially designates the accuser as “victim” or “survivor,” revealing the bias that the accuser is always right. The accuser would get extensive counseling, but for the accused, no legal representation, subpoena power or due process.

Most appalling, the accused is guilty based on a preponderance of evidence — meaning 51 percent of the facts — rather than evidence beyond a reasonable doubt.

When Harvard adopted a similar policy in 2014, 28 Harvard law professors, including liberal favorite Alan Dershowitz, objected that it lacked “the most basic elements of fairness and due process” and was “overwhelmingly stacked against the accused.”

Sen. Kirsten Gillibrand is pushing for legislation to apply the same “guilty until proven innocent” standard nationwide.

Gillibrand even invited Sulkowicz to be an honored guest at President Obama’s State of the Union Address.

Never mind that Sulkowicz’s sex partner is suing Columbia to get his reputation back, one of several dozen college men suing after being falsely tarred as sexual assailants.

House Speaker Nancy Pelosi, who came to New York earlier this month to campaign for Cuomo’s bill, claims sexual assault on campus is an “epidemic.”

The evidence shows otherwise. In fact, young women are at greater risk of being raped if they don’t attend college, according to a December 2014 Bureau of Justice Statistics report.

On campuses, the real danger is binge drinking — 40 percent of students do it — and the National Institutes of Health sees it as a major cause of date rape and other misconduct.

Instead of stripping college men of their legal rights and criminalizing dorm-room hook-ups, colleges should get serious about curtailing alcohol abuse. That’s the epidemic.

Cuomo says “as a father of two college-aged girls,” he’s making campus sexual assault “a personal issue.” But if Cuomo gets his way, as it appears he will, parents with sons should think twice about sending them to college in New York.

Betsy McCaughey is a senior fellow at the London Center for Policy Research.