Ryan Petersen said a lot of what Americans buy from China is "discretionary spend" — optional items that can be replaced if they become expensive.

The developments came as China has struck a publicly defiant tone and Trump sowed confusion by claiming that he had spoken with Chinese President Xi Jinping, which Beijing denied.

Nearly four weeks into a costly global trade war with no end in sight, Mr. Trump is facing a barrage of lawsuits from state officials, small businesses and even once-allied political groups, all contending that the president cannot sidestep Congress and tax virtually any import at levels to his liking.