The U.S. was already flirting with the first decline in economic growth in three years before President Donald Trump unveiled his latest round of tariffs on Wednesday. Now economists say two quarters of negative growth or even a recession can’t be ruled out.

The most far-reaching version of Trump’s strategy would raise the effective, or average, tariff on U.S. imports to about 20%, comparable to the heavy import duties the nation imposed in the 1930s and that contributed to the Great Depression,

The announcement of sweeping tariffs of at least 10% on U.S. imports rocked markets Thursday and had economists warning of dire times for the economy.