It is hard to recall a time in history when pragmatic U.S. leadership around the world mattered more to our nation’s security and prosperity. From the brutality of ISIS as they recruit foreign fighters, seize swaths of territory, kidnap innocent civilians, and murder Christians; to the appalling acts of Syrian President Bashar al-Assad killing his own people with barrel bombs and chlorine gas; to Russian President Vladimir Putin’s unlawful invasion and occupation of Ukraine; to China’s aggressive behavior in the East and South China Seas; the challenges we face are vast. But there is perhaps no greater geopolitical issue facing the world today than preventing a nuclear-armed Iran.