President Trump is asking the Supreme Court to act quickly to overturn a lower court decision stating that many of his tariffs are illegal because he doesn’t have the power to unilaterally institute them.

Mr. Trump wants the justices to consider the case on an “expedited” timeline, but it could still put any decision months away. He is asking justices to hear arguments in early November and issue a decision soon afterward.

A federal appeals court panel ruled seven to four last week in V.O.S. Selections v. Trump that the tariffs overstepped the president’s authority. It upheld a decision by a three-judge panel on the United States Court of International Trade that ruled that the International Emergency Economic Powers Act does not give the president “unbounded” authority to impose his “Liberation Day” tariffs.

“That decision casts a pall of uncertainty upon ongoing foreign negotiations that the President has been pursuing through tariffs over the past five months, jeopardizing both already negotiated framework deals and ongoing negotiations,” Solicitor General D. John Sauer said in a Supreme Court filing.

“The stakes in this case could not be higher,” he added.

Mr. Trump has made the tariffs a cornerstone of his economic policy since returning to the White House. He used the emergency economic powers to declare the federal trade deficit a national emergency and justify his import taxes.

“The Congress has never given the president such a sweeping power to just do it on his own,” the lawyer who represents the plaintiffs, Neal Katyal, said during a Bloomberg podcast after the appeals court ruling.

“The president has an easy fix, if he wants to. He can go to Congress and seek approval for the tariffs that he wants,” Mr. Katyal added.

The Constitution gives Congress the power to impose tariffs on imports but Congress has delegated its authority in recent decades by passing several laws allowing the executive branch to impose the levies in some circumstances. Two courts have now said that Mr. Trump’s tariffs fall outside what has been authorized by lawmakers.

“Obviously these tariffs are highly unpopular. But, nonetheless, the Congress is controlled by his party and that’s the place to start,” Mr. Katyal said. “Don’t run to the federal courts to do what you can’t do in Congress.”

The lower courts have allowed the tariffs to stay in place while the Trump administration appeals.

Members of the administration have claimed the country will suffer devastating economic consequences without the tariffs.

Mr. Sauer says millions of jobs will be eliminated and the future of Social Security and Medicare will be threatened if money already collected through tariffs has to be refunded to the American companies that paid them.

Secretary Scott Bessent claims that the large sums already collected will make it more difficult for the Supreme Court justices to rule against Mr. Trump. The White House has boasted that the administration has already collected a record $183 billion in taxes from imports.

Mr. Bessent previously indicated that by the time the Supreme Court decision comes it will mean billions of dollars more of tariff income will be at stake.