WASHINGTON (AP) — Appellate court judges expressed broad skepticism Thursday over President Donald Trump’s legal rationale for his most expansive round of tariffs.

Members of the 11-judge panel of the U.S. Court of Appeals for the Federal Circuit in Washington appeared unconvinced by the Trump administration’s insistence that the president could impose tariffs without congressional approval, and it hammered its invocation of the International Emergency Economic Powers Act to do so.

“IEEPA doesn’t even mention the word ‘tariffs’ anywhere,” Circuit Judge Jimmie Reyna said, in a sign of the panel’s incredulity to a government attorney’s arguments.

Brett Shumate, the attorney representing the Trump administration, acknowledged in the 99-minute hearing “no president has ever read IEEPA this way” but contended it was nonetheless lawful.

The 1977 law, signed by President Jimmy Carter, allows the president to seize assets and block transactions during a national emergency. It was first used during the Iran hostage crisis and has since been invoked for a range of global unrest, from the 9/11 attacks to the Syrian civil war.

Trump says the country’s trade deficit is so serious that it likewise qualifies for the law’s protection.

In sharp exchanges with Shumate, appellate judges questioned that contention, asking whether the law extended to tariffs at all and, if so, whether the levies matched the threat the administration identified.

“If the president says there’s a problem with our military readiness,” Chief Circuit Judge Kimberly Moore posited, “and he puts a 20% tax on coffee, that doesn’t seem to necessarily deal with (it).”

Shumate said Congress’ passage of IEEPA gave the president “broad and flexible” power to respond to an emergency, but that “the president is not asking for unbounded authority.”