Remember how conservatives used to mock the mainstream media’s supposed “obsession” with President Donald Trump? Well, since Democrats regained the House and clout on Capitol Hill, look at who’s obsessing over whom.

If you’re visiting the marble halls of the Capitol or a House office building and you see a scrum of news reporters stepping briskly toward you, there’s a good chance the newsmaker in the middle is the fastest-rising star in the freshman class of House members, Rep. Alexandria Ocasio-Cortez.

Her election made history as the most shocking upset of the midterms. The 29-year-old New York Democrat and self-described democratic socialist handily unseated then-Rep. Joseph Crowley, a seasoned Queens powerbroker and House Democratic Caucus chairman who had been considered a possible future speaker, in the primary. She won easily in the general election.

Conservative politicians and pundits pounced on this youngster who, like fellow democratic socialist Sen. Bernie Sanders, the former Democratic presidential candidate from Vermont, was calling for “Medicare for all,” tuition-free public colleges and trade schools — and raising the top marginal tax rate to 70 percent. That’s higher than it is now but lower than the 90 percent rate that top earners faced under President Dwight Eisenhower.

Let’s call it “AOC Derangement Syndrome.” In explaining her positions, every gaffe or factual error was trumpeted on Fox News or conservative websites, which held her up as a textbook example of leftist folly.

But that caricature didn’t stick outside of the usual conservative haunts. As the gap in income and job opportunities between rich and poor has grown, so have political pressures that have moved the Democratic Party to the left.

Sanders’ push for Medicare for all and free college tuition, for example, sounded like radical fringe ideas in 2016. But by last year’s midterms, when even some Republican incumbents felt compelled to reposition themselves as protectors of insurance coverage for pre-existing conditions, Medicare-for-all has been sounding more mainstream by the day.

Bullying AOC by Twitter trolling also backfired. Like Trump, she’s Twitter-fluent and does not hesitate to give as good _ or as sarcastically _ as she gets.

When conservative Max Boot, for example, penned a Washington Post column that described her as an underqualified Sarah Palin for the left, she clapped back with, “If you’re allowed to characterize female politicians as ‘unlikeable,’ are we allowed to describe takes like these ‘resentful?’ “

That’s the sort of fearless feistiness that impresses a cohort of conservatives that Politico magazine calls “Ocasio-Cortez’s far-right fan club.”

“AOC has what I call ‘gameness’ or competitive heart,” Steve Bannon, Trump’s former chief strategist, told Politico, “the combination of grit, determination, fighting spirit that you can’t coach. You either have it or you don’t, and she has it big league.”

Rep. Matt Gaetz, a second-term Florida Republican and outspoken Trump supporter went even further: “I aspire to be the conservative AOC,” he told the magazine, although unfortunately, “I can’t dance for s—-.

That last remark about dancing refers to a leaked video from her college days that right-wing Twitter users shared in a botched attempt to embarrass her. The video of her and fellow Boston University students happily performing a dance scene from “The Breakfast Club” went viral, drew millions of views and an appreciative message from the 1985 movie’s two female leads, Molly Ringwald and Ally Sheedy. “That’s it, Alexandria,” Ringwald tweeted, “you’re in the club.”

But all has not been rosy for the notorious AOC in her own party on Capitol Hill. She infuriated colleagues by aligning with Justice Democrats, a progressive outside group that threatens to back left-wing challengers to entrenched Democrats in the way that AOC unseated Crowley. The Hill, a Capitol Hill-focused newspaper, reported this past week that some of those lawmakers are turning the tables to discuss recruiting a primary challenger to run against AOC.

Both she and Justice Democrats denied plans to challenge lawmakers in the New York delegation. So far, no one in New York’s delegation has announced plans to challenge her either. In fact, despite her early bravado in joining a protest for a “Green New Deal” agenda outside now-Speaker Nancy Pelosi’s office, she voted for Pelosi and has been a loyal, if occasionally outspoken, team player.

She’s learning. She’s been a good soldier for her party while maintaining her right to criticize its establishment. Despite calls by old-timers to rein her in, the party needs charismatic and energetic youngsters like her to help improve turnout among young voters who are much less likely than their elders to show up at the polls.

And AOC has a lot to teach. She already has demonstrated how Trump’s bag of tricks — a populist voice, a vigorous social media presence, a sarcastic critique of mainstream media gatekeepers and a refusal to be daunted by fact-checkers or party leaders — are likely to become standard political tools in an age in which everyone can have their own soapbox whenever they tweet.