The U.S. Supreme Court on Monday told President Donald Trump that he can't just fire Federal Reserve Governor Lisa Cook on a whim — at least not without following the rules.

In a 5-4 ruling, the court said Trump hadn't followed the procedures required under federal law to remove Cook from the Fed's Board of Governors, according to Reuters.

Chief Justice John Roberts, who wrote the majority opinion, said Trump "failed to afford Cook the procedural protections to which she was entitled by statute."

The whole mess started in August 2025, when Trump tried to boot Cook over allegations of mortgage fraud — charges she flatly denies. The ruling now sends the case back to lower courts, where Cook will get a chance to fight the allegations on the merits.

Roberts made it clear that Federal Reserve governors don't serve "at the president's pleasure" and can only be removed "for cause." That's a big deal for the Fed's independence, which the court seemed keen to protect.

"We see no reason to leave the public in limbo, or to sow doubt as to the status of one of our nation's (and the world's) most important financial institutions," Roberts wrote.

Trump, unsurprisingly, had a different take. In a post on Truth Social, he said the Supreme Court returned the case on "a strictly procedural basis" and vowed to "take appropriate action immediately" to ensure "someone who has committed wrongdoing" doesn't make decisions affecting the U.S. economy.

Cook wasn't having any of it. She rejected Trump's characterization, saying the case "was never about mortgage documents signed years before I became a Federal Reserve governor." Instead, she called the allegations "a manufactured pretext because I refused to bow to political pressure."

This is the first time a U.S. president has tried to remove a sitting Federal Reserve governor, which makes it kind of a big deal. The Fed's independence has long been a cornerstone of U.S. economic policy, and this ruling reinforces that governors aren't political pawns.

Senator Elizabeth Warren (D-Mass.) weighed in on X, saying the ruling confirmed Trump's attempt to fire Cook was illegal. But she warned that Trump's effort to take over the Federal Reserve "is far from over."

Trump has been a vocal critic of the Fed's interest-rate policy, repeatedly calling for lower borrowing costs under former Chair Jerome Powell. So this fight probably isn't going away anytime soon.