Trump had said he badly wanted to attend the arguments, but ruled out what would have been a highly unusual appearance, saying it would have been a distraction. "It's not about me, it's about our country," he told reporters Sunday.
On Monday, his top economic adviser said he would be there instead, signaling the importance of the case to the Trump administration. Asked whether his presence could be criticized as trying to intimidate the justices, Bessent told Fox: "They can say what they want. I am there to emphasize that this is an economic emergency."
The U.S. Supreme Court is set to hear arguments on whether the Republican president overstepped federal law when he used the International Emergency Economic Powers Act, or IEEPA, to set sweeping import taxes.
Earlier this year, lower courts determined that the president did not have the power under IEEPA to set tariffs, but left them in place while the Supreme Court considered the issue.
Bessent described the hearing as "a matter of national security." But he has said there are contingencies in place. Last month, he told a group of reporters that in the event the court rules against the Trump administration, "there are lots of other authorities that we can operate under."