The Supreme Court Thursday morning tossed aside conservatives' latest challenge to the Affordable Care Act, rejecting the Trump administration’s bid to get the entire health care law thrown out.

Why it matters: The 7-2 ruling will allow the ACA, which covers some 20 million people and has been the law of the land for 11 years, to continue operating. It also shows there are some limits to how much of the Republican agenda can be accomplished through the courts, even with a solid conservative majority.

Details: The court said Republican attorneys general did not have the legal standing to bring their lawsuit, which aimed to get the entire ACA struck down. It's the third time the Supreme Court has saved the law.

How we got here: The ACA required most Americans to either purchase health insurance or pay a tax penalty. When the law first passed, that mandate was seen as essential to making the law’s other provisions work, particularly its protections for people with pre-existing conditions.

• In 2012, the Supreme Court upheld the mandate as an exercise of Congress' taxing power. The federal government couldn't simply require people to buy insurance, the court said, but it could tax their decision not to do so.
• In 2017, as part of the GOP's tax cut package, Congress zeroed out the penalty for being uninsured, nullifying the individual mandate.
• A group of Republican attorneys general then sued. The tax penalty was now gone, and all that remained was the part that said Americans had to buy insurance. So, they argued, the mandate had become unconstitutional — and the rest of the law had to fall along with it.

But the court ruled on Thursday that the states that brought the suit could not show that they'll suffer any injury from the fact that some form of the mandate is still in effect, and threw out the lawsuit as a result.

• Justice Stephen Breyer wrote the majority decision. Justices Samuel Alito and Neil Gorsuch dissented.
• The states' lawsuit should have been able to proceed, Alito argued. The shell of the mandate is "clearly unconstitutional, and to the extent that the provisions of the ACA that burden the States are inextricably linked to the individual mandate, they too are unenforceable," he wrote.

What they’re saying: "A big win for the American people," President Biden tweeted. "There’s no better day than today to sign up for quality, affordable health care at HealthCare.gov. With millions of people relying on the Affordable Care Act for coverage, it remains, as ever, a BFD. And it’s here to stay."

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