Khosrow B. Semnani, an Iranian-American philanthropist, is the author of “Where Is My Oil? Corruption in Iran’s Oil and Gas Sector” and “The Ayatollah’s Nuclear Gamble.”

As with Berlin in the midst of the Cold War, Iran is an early and urgent test case about the nature of America’s commitment to restoring a liberal world order.
Fortunately, President Donald Trump is taking a measured approach to a most difficult situation.