President Trump warned that U.S. negotiations with Tehran were on "life support," citing Iran's insistence on maintaining control of the Strait of Hormuz. Before the current conflict, a fifth of the world's oil supply flowed through this critical passage. Iranian attacks on vessels and a U.S. blockade of Iranian ports have now trapped thousands of ships in the Persian Gulf, triggering a global economic crisis.

This isn't the first time the strait has become a flashpoint. During the Iran-Iraq war in the 1980s, Iranian forces intercepted ships bound for Iraq and its allies, sparking a deadly naval conflict that killed more than 400 civilian sailors and damaged 500 commercial vessels. A U.S. commander told a 2012 congressional hearing: "If you ask me what keeps me awake at night, it's the Strait of Hormuz."

The dispute is fundamentally legal. The U.S. argues for freedom of navigation through the strait, while Iran claims the right to regulate traffic in what it considers its territorial waters. Neither Washington nor Tehran has ratified the U.N. Convention on the Law of the Sea, though it reflects customary international law. The crisis now looms over Trump's summit with China's President Xi Jinping later this week, as Trump urges Xi to pressure Iran to reopen the waterway.