Dr. Ben Carson told supporters Sunday that he supports increased military involvement in Syria because ISIS is an existential threat to the United States, adding that al Qaeda — the group behind the 2001 September 11th attacks— was not. "A lot of Americans really think back to 2003, and they remember Saddam Hussein and al Qaeda," Carson explained at a Nevada rally. "They say, 'we never should have gone in there and destabilized it.' And they may be right about that." "But here's the problem, Saddam Hussein and al Qaeda at that time was not an existential threat to us....