Too few people realize the full extent of Iran’s role in backing terrorist groups across the Middle East, from Hamas in Gaza to Hezbollah in Lebanon and the Houthis in Yemen. Even fewer are aware of Iran’s expanding influence in the Western Hemisphere, threatening regional stability and U.S. security at an alarming level. But we can’t afford to ignore the threat any longer. It’s time for the U.S. to act, forging a comprehensive plan with our allies to preempt Iran’s geopolitical ambitions in our own neighborhood.