India, Jan. 10 -- The Trump administration is preparing to rely on alternative legal authorities to rapidly reimpose tariffs if the Supreme Court invalidates the president's sweeping global levies, National Economic Council Director Kevin Hassett said.

"We've got a very, very detailed backup plan. We're confident that if we were to lose this case, that we can get all of the president's policies in place almost immediately with alternative authorities," Hassett said Friday on Fox News.

The Supreme Court held its first opinion day of the year on Friday, but did not issue a ruling on the legality of the tariffs imposed under the International Emergency Economic Powers Act. The decision is expected to have implications for Trump's reciproca...