President Trump is invoking an unused provision of the 1930 Smoot-Hawley Tariff Act to impose additional tariffs on Canada over alleged discrimination against U.S. exports.

Why it matters: As the Supreme Court limits Trump’s ability to wield tariffs and a temporary tariff stopgap expires, the president is turning to a rarely used tariff authority.

While the Smoot-Hawley Act is often blamed for worsening the Great Depression, this provision went unused — until now.

Driving the news: Trump on Monday announced an additional 50% tariff on select Canadian imports that would take effect in August under Section 338 of the Tariff Act of 1930, better known as the Smoot-Hawley Tariff Act after its congressional sponsors.

The administration says the measure responds in part to Canada’s retaliation against earlier U.S. tariffs and will affect about $20 billion in Canadian goods.

It is another setback for Canada after the administration declined to immediately renew the current protections and framework of the U.S.-Mexico-Canada Agreement.

Read the article.