President Donald Trump raised the global duty on imports into the United States to 15 percent on Saturday, doubling down on his promise to maintain his aggressive tariff policy a day after the Supreme Court ruled much of it illegal.

Trump said on his Truth Social platform that after a thorough review of Friday's "extraordinarily anti-American decision" by the court to rein in his tariff program, the administration was hiking the import levies "to the fully allowed, and legally tested, 15% level."

Shortly after the court's 6-3 ruling that rejected the president's authority to impose tariffs under a 1977 economic emergency powers act, Trump had initially announced a new 10 percent global levy by invoking a different legal avenue.

At the same time, the Republican launched an extraordinary personal attack on the conservative justices who had sided with the majority, slamming their "disloyalty" and calling them "fools and lap dogs."

The ruling was a stunning rebuke by the high court, which has largely sided with the president since he returned to office, and marked a major political setback in striking down Trump's signature economic policy that has roiled the global trade order.

Saturday's announcement is sure to provoke further uncertainty as Trump carries on with a trade war that he has used to cajole and punish countries, both friend and foe.

It is the latest move in a process that has seen a multitude of tariff levels for countries sending goods into the United States set and then altered or revoked by Trump's team over the past year.

The new duty by law is only temporary -- allowable for 150 days. According to a White House fact sheet, exemptions remain for sectors that are under separate probes, including pharma, and goods entering the US under the US-Mexico-Canada agreement.

On Friday, the White House said US trading partners that reached separate tariff deals with Trump's administration would also face the new global tariff.

High court defeat
Friday's court ruling did not impact sector-specific duties Trump separately imposed on steel, aluminum and various other goods. Government probes still under way could lead to additional sectoral tariffs.

But it nevertheless marked Trump's biggest defeat at the Supreme Court since returning to the White House 13 months ago. The court has generally expanded his power.

Trump heaped praise on the conservative justices who voted to uphold his authority to levy tariffs -- Clarence Thomas, Samuel Alito and Brett Kavanaugh, a Trump nominee -- thanking them "for their strength and wisdom, and love of our country."

The president alleged the majority of six justices, including two nominated during his first term, had been "swayed by foreign interests."

"I think that foreign interests are represented by people that I believe have undue influence," he said.

Shares on Wall Street -- a metric closely watched by Trump -- rose modestly Friday after the decision, which had been expected.

Business groups largely cheered the ruling, with the National Retail Federation saying this "provides much-needed certainty" for companies.

In court arguments, the Trump administration said companies would receive refunds if the tariffs were deemed unlawful. But the Supreme Court's ruling did not address the issue.

Trump said he expected years of litigation on whether to provide refunds. Kavanaugh noted the refund process could be a "mess."

Several countries have said they are studying the Supreme Court ruling and Trump's subsequent tariff announcements.

German Chancellor Friedrich Merz said Saturday he would hold talks with European allies to formulate "a very clear European position" and joint response to Washington before he travels to the US capital in early March.

On the domestic front, Pennsylvania Governor Josh Shapiro, a Democrat, said on X it was time for Trump to "listen to the Supreme Court, end chaotic tariffs, and stop wreaking havoc on our farmers, small business owners, and families."