Trump tariffs tested in court as challengers seek to block them

President Trump’s “Liberation Day” tariffs faced their most significant legal scrutiny yet Tuesday as a group of small businesses asserted to a three-judge panel that Trump exceeded his authority.

The New York-based U.S. Court of International Trade spent most of Tuesday’s two-hour argument questioning how it could draw a manageable legal standard in adjudicating Trump’s April 2 tariff announcement, which has disrupted financial markets and reshaped global trade flows.

Trump...