WASHINGTON

US President Donald Trump said Thursday that his administration would need a backup plan in case the Supreme Court strikes down tariffs he unilaterally imposed on dozens of countries.

Trump made the remarks one day after a majority of the Court's nine justices expressed skepticism about the constitutionality of the president's tariff campaign. He sought to defend them by claiming they are part of the country's "national security," and saying he hopes "we're going to win that case."

"So much evolves around tariffs as a defensive mechanism for our country, as national security for our country," Trump told reporters in the Oval Office, where he was hosting an event on new deals with pharmaceutical companies to lower the prices of GLP-1 weight loss drugs.

"We thought we did very well yesterday. We hope that we did. I think it would be devastating for our country, but I also think that we'll have to develop a game two plan. We'll see what happens. Most people tell me we did very well legally," he added.

Members of the top court's liberal and conservative wings questioned Solicitor General D. John Sauer about how the administration implemented the tariffs without violating the taxation authorities granted to the US Congress under the Constitution.

"These are regulatory tariffs. They are not revenue-raising tariffs," said Sauer. “The fact that they raise revenue was only incidental."

One of the three liberal judges on the court, Sonia Sotomayor, told Sauer: “You say tariffs are not taxes, but that’s exactly what they are. They’re generating money from American citizens, revenue," adding that only Trump has utilized the International Emergency Economic Powers Act (IEEPA) to levy tariffs.

Lower courts had ruled that Trump did not have legal authority under the IEEPA to impose fentanyl-related tariffs on goods from Canada, China and Mexico, as well as reciprocal duties on imports from other US trading partners.

One of the six conservative justices, Neil Gorsuch, questioned Sauer about Trump's unilateral imposition of the tariffs without congressional approval, citing an international emergency.

“What happens when the president simply vetoes legislation to take these powers back?" Gorsuch asked.

Sauer was also under pressure from other conservatives, including Chief Justice John Roberts and justices Amy Coney Barrett, Brett Kavanaugh and Samuel Alito.

The justices questioned Sauer for more than an hour before Neal Katyal, the plaintiffs' attorney, started presenting his case.

"Tariffs are taxes," Katyal began, reiterating the point that several justices had brought up against Sauer. “Our founders gave that taxing power to Congress alone.”