Fifty years ago, on November 24, 1961, President John F Kennedy, officially authorized the wear of the distinctive headgear of the Green Beret for US Army Special Forces. It was a decision that overrode the opinions of conventional Army Generals at the time and the result of the commander of US Army Special Forces at Ft Bragg, NC risking the backlash from conventional officers by ordering the wear of the unauthorized headgear in a parade the President was watching.
Ever since, people inside and outside the military have confused Special Forces with the hat they wear. Special Operations is the type of Warriors they are. Green Berets are the headgear they wear (when not in the field). Special Forces is the title they've earned.
They trace their roots back to the joint US-Canadian units in WWII called the 1st Special Services Force and to the OSS, which also gave birth to the CIA. They were fighting in Viet Nam and Indonesia, years before they were authorized a beret and before the currently reported "start of the war" there. It was a few dozen or less Special Forces in Lang Vei that defeated a North Vietnamese Tank Regiment, ahead of the Tet Offensive, that inspired the book and move "The Green Berets" by Robin Moore, and starring John Wayne.
They were fighting in Nicarauga and El Salvador, when malcontents were protesting against the war against communism. They were overstretched before 9/11 and have been busy since. It was 200 men of 5th Special Forces Group (Airborne) that infiltrated Afghanistan and led the war overthrowing the Taliban government there in the fall of 2001.
Special Forces are "The Quiet Professionals" that do more, without accolades, during war and during peace to protect America. For a more complete history of US Army Special Forces, read it from those that made that history: Professional Soldiers History.