On This Day: U.S. invades Panama On Dec. 20, 1989, the United States invaded Panama to oust Manuel Noriega and install the duly elected civilian government. By (0) Marines of Company D, 2nd Light Armored Infantry Battalion, stand guard with their LAV-25 light armored vehicles outside a destroyed Panamanian Defense Force building during the first day of Operation Just Cause on December 20, 1989. File Photo courtesy the U.S. Marine Corps On December 20, 1968, the so-called Zodiac Killer killed his first two confirmed victims -- David Faraday, 17, and Betty Lou Jensen -- in Vallejo, Calif. File Image courtesy of the San Francisco Police Department