Going into 2020, Gropey Uncle Joe was always going to be a problem for the Dems. That Joe Biden himself doesn’t see that tells us all we need to know.

Biden’s inappropriate behavior towards women isn’t recent, nor is it secret. Google any variation of “Joe Biden,” “creepy,” or “cringe” and no shortage of images, videos and articles come up, all the same. Here’s Joe Biden standing behind women and girls of all ages, massaging their shoulders, rubbing their backs, nuzzling their hair, whispering into their ears, sometimes offering clearly unwanted kisses, their faces, to a one, silently pleading: “Stop!”

In 2015, Biden massaged the shoulders of Ash Carter’s wife, Stephanie, during Carter’s swearing in as defense secretary; Carter actually turned, mid-speech, and put his own hand on his wife’s shoulder to make Biden step away. And though Stephanie wrote an essay for Medium defending Biden for comforting her as she was “uncharacteristically nervous,” many women watching were made extremely uncomfortable.

During Sen. Chris Coons’ swearing in earlier that same year, Biden leaned down, cooed in his 13-year-old daughter’s ear and kissed her, all as the girl kept pulling away. Her mother had to tap Biden’s shoulder several times to force him back. In an interview that followed with Fox News Sunday host Chris Wallace, Coons similarly downplayed what we all saw.

“I have to ask, ’cause a lot of people have been speculating about it — does [your daughter] think the vice president is creepy?”

“No, Chris,” Coons replied. “She doesn’t think the vice president is creepy.”

But those two incidents started a national conversation: What is wrong with Joe Biden?

What the vice president doubtless sees as merely problematic metastasized on Friday when Lucy Flores, a former Nevada assemblywoman, posted an essay on New York magazine’s The Cut.

Headlined “An Awkward Kiss Changed How I Saw Joe Biden,” Flores detailed an unnerving encounter with the vice president in 2014 after he volunteered to stump for her.

As she gathered herself before taking the stage, she writes, “I felt two hands on my shoulders. I froze. ‘Why is the vice president of the United States touching me?’ I felt him get closer to me from behind. He leaned further in and inhaled my hair. I was mortified. I thought to myself, ‘I didn’t wash my hair today and the vice president of the United States is smelling it.’ … He proceeded to plant a big slow kiss on the back of my head. My brain couldn’t process what was happening.”

It was just three days before Election Day. Flores writes that even in the savage realm of politics, she had never experienced anything as disturbing and invasive. She asked herself, “What in the actual f—k?”

Great question. Since then, another woman has come forward, claiming that Biden grabbed her head at a Connecticut fundraiser in 2009, “put his hand around my neck and pulled me in to rub noses with me … I thought he was going to kiss me on the mouth.”

So much of Biden’s agonizing over a 2020 run has been assumed to be over his age (78) and messy family dynamics. As Page Six exclusively reported in 2017, after Biden’s 46-year-old son Beau died of brain cancer in 2015, Beau’s brother Hunter began an affair with Beau’s widow, leaving his own wife of 23 years, Kathleen, with whom he has three children. The scandal was believed to be a key factor in Biden’s decision to sit out 2016.

Time’s Up and #MeToo aside, Biden faces intra-party upset over his support of Bill Clinton’s 1994 crime bill; his brutish questioning of Anita Hill; and, most recently, for taking $200,000 for a speech in October boosting a House Republican just before the midterms.

But to be a standard-bearing centrist in a progressive-moving party is the least of his concerns. It’s his behavior with women — and young girls — that’s the far stickier problem, one the Democratic Party is beginning to address in unison.

Sure, there are still ideologues who blame Kirsten Gillibrand for Al Franken’s own #MeToo resignation rather than Franken, or those who will point to President Trump’s “Grab them by the p—y,” the number of sexual harassment claims against him, and say: So what? This election is too high-stakes to forfeit a front-runner.

Here’s the thing: We are no longer willing to define deviancy down. The record number of women elected to Congress in 2018 was a direct response to this kind of dismissive, ridiculous argument. As The Post reported on Sunday, some of Biden’s most high-profile challengers — Elizabeth Warren, John Hickenlooper, Amy Klobuchar — are refusing to defend Biden. A cynic could obviously point to kneecapping a rival, but it’s worth noting that Bernie Sanders, himself of Biden’s generation and facing issues of sexual harassment among staff on his own 2016 campaign, declined to malign a possible front-runner. Incredibly, Sanders has said he’s unsure Biden should be disqualified for this “one incident alone.”

Really? One incident alone?

The Onion spoofed Biden’s sleaziness as early as 2009. Left-leaning outlets including the Daily Beast and the Washington Post criticized Biden’s lechery toward Carter’s wife. Even the Huffington Post has called Joe Biden “a terrible idea in a post-Weinstein America.” And Byron York, writing for the conservative Washington Examiner, referenced this salient Biden quote from October 2000 regarding the Violence Against Women Act:

“There is no circumstance under which a man has a right to touch a woman without her consent, other than self-defense,” Biden said. “We are changing the attitudes of America about what constitutes appropriate behavior on the part of a man with a woman.”

If that’s the truth, creepy Uncle Joe won’t be running.