'Monumental ruling': Expert reacts as Supreme Court hits Trump's favorite policy

President Donald Trump's agenda just got dealt a "monumental" defeat by the U.S. Supreme Court, according to a legal expert.

The court ruled 6-3 against the 79-year-old president's sweeping tariffs by finding that his invocation of an emergency statute to regulate global trade was unlawful, and CNN's Elie Honig explained the implications of the decision on "The Situation Room."

"It's a monumental ruling," Honig said, "and the bottom line is that the tariffs Donald Trump announced back in April on 'Liberation Day' are gone.