WASHINGTON — The Supreme Court’s stunning rebuke of President Donald Trump’s most sweeping tariffs means he can’t conjure up new import taxes on a whim anymore. But the justices’ ruling on Friday is nonetheless unlikely to ease the uncertainty over Trump’s trade policy that has paralyzed businesses over the past year. “It’s only gotten more complicated for everybody,’’ said trade lawyer Ryan Majerus, partner at King & Spalding and a former U.S. trade official. Vexing questions remain: How will the president use other laws to reconstruct the tariffs the Supreme Court knocked down, and will those attempts withstand legal challenges? What does the decision mean for the trade deals Trump strong-armed other countries into accepting, using his now-defunct tariffs as leverage? Can importers collect refunds for the tariffs they paid last year, and if so, how? Then there’s Trump’s own unpredictability. Even though he had weeks to prepare for an unfavorable Supreme Court ruling, his response was still chaotic: On Friday, he said he’d use other legal authority to impose 1