A White House statement said: "We expect this ruling will be appealed to the Supreme Court. Pending the appeal process, the law remains in place."

• "The ruling was over a lawsuit filed this year by a group of Republican governors and state attorneys general," per the N.Y. Times.
• U.S. District Court Judge Reed O’Connor in Fort Worth, a George W. Bush appointee, wrote that the individual mandate requiring people to have health insurance "can no longer be sustained as an exercise of Congress’s tax power."

The big picture: This was an amazingly broad ruling. The judge didn't just strike down everything that's related to the individual mandate. He struck down everything, period.

• That includes the parts that everyone likes, like the expansion of Medicaid, young adults staying on their parents' plans — and, of course, coverage of pre-existing conditions.
• Nothing happens right away. The ruling will be appealed, there's no injunction to shut down the law right now, and the Trump administration is making it clear the law stays in place for now.

Why it matters: You should take this ruling seriously. It's getting a lot of criticism from legal experts, including ACA critics, and it could be overturned — but it won't definitely be overturned. This really could end with the ACA being wiped out.

• The ACA has already survived two near-death experiences with the Supreme Court — over the mandate in 2012 and subsidies in 2015.
• But that was before the Kavanaugh Court. If this ruling gets that far, the justices could say the ruling went too far and overturn it.
• But there’s no guarantee that a more conservative court won’t just let the law die.

Political fallout: This could be a nightmare for Republicans in suburbs and swing states.

• The midterms proved that the ACA has gotten more popular since the GOP started trying to repeal it — especially the protections for pre-existing conditions.
• If the law goes away, that goes with it. This is not the fight Republicans want to have. 

• Trump blurted out his decision with a 5:18 p.m. Friday tweet, amid coverage of how few top people wanted the job. (On CNN, the job was compared to hosting the Oscars. Trump tweeted: "For the record, there were MANY people who wanted to be the White House Chief of Staff.")
• Trump announced Mulvaney as "Acting" chief of staff, a puzzling wrinkle which prolongs the instability that a new chief of staff presumably would be tasked with vanquishing.

White House insiders expect Mulvaney to get the permanent gig.

• But Trump keeps control and doesn't fully empower his guy, reminding Mulvaney who the real chief of staff is: No funny business like General John Kelly tried to pull, restricting enablers' access to POTUS.
• This is exactly why some other candidates didn't take the job or didn't get the job: They would have insisted on changes Trump doesn't want to make.
• A senior administration official who spoke to reporters at the White House said: "There’s no time limit." Asked why Mulvaney was named "acting," the official said: "Because that’s what the president wants."
• A White House statement last night said: "Mick Mulvaney will not resign from the Office Of Management and Budget, but will spend all of his time devoted to his role as the acting Chief Of Staff for the President. Russ Vought will handle day to day operations and run OMB."

After all the drama around the pick, numerous Trump allies — inside and out — told me they think the pick is a pretty good idea and has as good a chance of working as anything.

• Mulvaney, 51 (bi0) is a former congressman from South Carolina who has the toughness, Hill connections and political skills Trump will need amid a re-election race, a hostile House and impeachment/Mueller drama.
• Their personal chemistry is great — a key criterion for Trump. Mulvaney is one of the very few administration officials who golfs with Trump. "And Mick is actually a good golfer," said one insider. "Trump respects that."

The WashPost has the sentence of the day: "Mulvaney has an easy rapport with Trump, often taking large charts and colorful graphics into the Oval Office to explain fiscal policy, administration officials said."

Above, White House budget director Mick Mulvaney discusses a possible government shutdown 11 months ago.

• Shutdown watch: Deadline Friday night to avoid partial federal government shutdown. The House is taking an extended five-day weekend, returning Wednesday night. Senate returns Monday. Ball is in Trump's court. (AP)