Stock futures tumbled Sunday night to kick off a new trading month, as investors weighed new U.S. tariffs on goods from key trade partners and their potential impact on the economy and corporate profits.

British Prime Minister Keir Starmer said Sunday that he would seek a strong trade relationship with the U.S. after President Donald Trump suggested he would slap Europe with tariffs after he hit America’s biggest trading partners — Canada,

The president’s trade assault, which makes no distinction between ally and adversary, is an assertion of U.S. dominance with significant risks.