Brent Scowcroft, the only national security adviser to serve under two presidents, has died at 95 from natural causes, according to NBC News. The former Air Force general held the national-security positions under both Gerald Ford and George H.W. Bush, earning recognition as a preeminent expert on international affairs and was a key White House figure during the Gulf War.

“Brent Scowcroft was an American patriot and public servant of the highest order with an extraordinary military and government service career spanning over 60 years,” a statement from the Scowcroft Group reads. “His entire professional life was devoted to how best to protect America and advance its interests. He mentored two generations of American public servants who revered him for his brilliance, integrity, humility and fundamental decency.”