Last week, an undisclosed number of U.S. Air Force B-2 Spirit stealth bombers engaged hardened underground weapons facilities in Yemen. According to the Defense Department, the B-2s were part of a broader operation aimed at destroying weapons Houthi rebels have been using to indiscriminately attack civilian and military vessels traversing the international waters of the Red Sea and Gulf of Aden in recent months. But the use of these aircraft was seemingly also meant as a message to the Houthi’s financial benefactors in Iran.