The U.S. is using force in the Strait of Hormuz and diplomacy in New York in an effort to break Tehran's chokehold on the vital shipping lane. Why it matters: Iran has already shown it's willing to respond with force, putting the two countries on the verge of a return to full-fledged war. Driving the news: President Trump announced an initiative to "guide" commercial vessels through the strait starting on Monday morning, and Iran threatened to fire on ships that did not coordinate with its mili