Many of the troops and ships once at the president’s disposal have shifted to the Caribbean.The Trump administration has insisted it has numerous military options to deploy against Iran if the regime uses force against demonstrators. But that menu is far more limited than it was even a year ago. The U.S. troops and ships that were once at the president’s disposal have shifted to the Caribbean. A major American defense system sent to the Middle East last year has returned to South Korea. And administration officials say there are no plans for the movement of major assets. The president...