BOSTON — The feds finally moved on Mayor Michelle Wu — but instead of perp-walking her out of City Hall, they filed a lawsuit.

Trump’s Department of Justice dropped the hammer Thursday, suing Wu, Boston, and the police department for what prosecutors call one of the worst sanctuary city schemes in America. At the center is Wu’s Trust Act — the policy that tells Boston cops to look the other way when ICE comes knocking.

This showdown didn’t come out of nowhere. Late last month, Attorney General Pam Bondi’s office sent Wu a scorching warning: tear down the sanctuary rules or face the consequences. Wu fired back with her usual defiance, blasting the feds for “attacking our cities” and swearing Boston wouldn’t bend. ICE ratcheted up the pressure, threatening to “flood the zone” with agents until City Hall got the message.

Now the DOJ has had enough. “Boston has been among the worst sanctuary offenders in America,” Bondi declared. “They explicitly enforce policies designed to undermine law enforcement and protect illegal aliens from justice.”

Wu’s response? Spin it into a campaign ad. Within hours she blasted the lawsuit as an “unconstitutional attack,” bragged Boston is “the safest major city in the country,” and vowed: “We will not yield.”

But critics say Wu isn’t just defending “the city.” She has made herself the face of sanctuary defiance across New England — baiting the feds, burning taxpayer dollars, and shielding some of the worst offenders in the region. ICE points to names like Marcelino De Leon Yoc, a Guatemalan sex offender accused of raping a child, and John Tobón Vargas, a Colombian national charged with kidnapping and aggravated rape, as examples of dangerous criminals who walked free because of sanctuary rules. Others include Luciano Pereira De Oliveira, accused of child rape and child porn, and Jose Wilfredo Lopez-Martin, charged with attacking victims using a hammer and his car.

These are not abstract policy fights. They are flesh-and-blood cases of violent offenders slipping back into communities because Wu would rather wage an ideological battle than cooperate with law enforcement.

Now Wu’s political grandstanding has dragged Boston taxpayers into the crossfire. The DOJ’s case could cost millions in legal fees — while residents live with the fallout of sanctuary laws that put criminals back on the street.

What was billed as a legal case has already morphed into a political circus — Wu grandstanding as a martyr while the feds methodically build their case. But unlike City Hall’s slogans, the DOJ isn’t bluffing: Boston is in federal court, Wu is on the hot seat, and the shield she’s built for criminal aliens is finally under fire.