President Trump was sued Thursday over the 20 percent tariffs he imposed on Chinese goods in the weeks leading up to Wednesday’s broader announcement.

It marks the first known legal challenge against Trump’s tariffs, which have fulfilled a campaign promise and rattled financial markets.

The lawsuit contests Trump’s use of the International Emergency Economic Powers Act of 1977 (IEEPA), arguing the law authorizes asset freezes and similar economic sanctions, but not tariffs. 

“Congress passed the IEEPA to counter external emergencies, not to grant presidents a blank check to write domestic economic policy,” the lawsuit states. 

The suit was brought by the New Civil Liberties Alliance (NCLA), a conservative legal advocacy group, on behalf of Simplified, a Florida-based small business that sells planners and purchases products from China. 

Filed in federal court in Pensacola, Fla., the suit asks a judge to declare Trump’s Chinese tariffs unlawful and block their implementation. 

Trump first imposed a 10 percent tariff on Chinese goods in a Feb. 1 executive order and then doubled it in another order issued March 3. 

Both came before Trump’s broader tariff announcement on Wednesday, which imposes a 10 percent general tariff on imports to the U.S. and higher rates for dozens of countries. It slapped China with an additional 34 percent tariff, creating a combined total of 54 percent.

“But in the IEEPA’s almost 50-year history, no previous president has used it to impose tariffs. Which is not surprising, since the statute does not even mention tariffs, nor does it say anything else suggesting it authorizes presidents to tax American citizens,” the lawsuit states. 

The Hill has reached out to the White House for comment.