Talks between the U.S. and Iran have collapsed, leading President Donald Trump to order a naval blockade targeting ships at Iranian ports via the Strait of Hormuz. While the U.S. military claims it is not a total shutdown, the move is a major escalation that has already sent shockwaves through the global economy. The Strait of Hormuz carries one-fifth of the world’s oil, and the blockade could remove 2 million barrels of Iranian oil from the market daily, pushing prices above $100 a barrel.