Trump’s Iran strategy is working and teaching our foes what deterrence means

President Donald Trump didn’t start this war. The Islamic Republic did — on Nov. 4, 1979, when it invaded the U.S. Embassy in Tehran and held 52 Americans hostage for 444 days. For nearly half a century, the world’s leading state sponsor of terrorism has killed and maimed more Americans than any other terrorist regime on Earth. It even plotted twice to assassinate Trump himself.

The regime’s attacks against the United States and our allies are not a series of isolated incidents, but a single...