Winter Soldier documents the "Winter Soldier Investigation" conducted by Vietnam Veterans Against the War (VVAW) in Detroit, Michigan in the winter of 1971. A call went out from VVAW to veterans all over the country saying, in effect, 'everyone is talking about the war that you know from the inside. If you want to have anything to say about it, come to Detroit and tell it like you saw it.' At the investigation, over 125 veterans representing every major combat unit to see action in Vietnam, gave eye-witness testimony to war crimes and atrocities they either participated in or witnessed. The purpose of the investigation was to bring to light the nature of American military policy in Vietnam.
Good Wiki page here, which includes the explanation for the phrase 'Winter Soldier':
The name "Winter Soldier Investigation" was derived from Thomas Paine's first Crisis paper written in December 1776, Valley Forge, Pennsylvania, in which he wrote:
"These are the times that try men's souls. The summer soldier and the sunshine patriot will in this crisis, shrink from the service of his country; but he that stands it now, deserves the love and thanks of man and woman."
Paine's words were written to inspire American patriots that remained after several defeats - the "sunshine patriots" and "summer soldiers" having deserted at Valley Forge because the going was rough. In contrast with the "sunshine patriots," those patriots who chose to continue to fight even in rough times were thus by implication "winter soldiers."
John Kerry, of course, was very anti-Viet Nam war back in the day, and he - as best we can tell - was somehow associated with the Winter Soldier Investigation. Which reminds us that we never saw Kerry's Going Upriver movie - maybe we'll get around to it someday.
We wonder, is there someone organizing a Winter Soldier Investigation for the Iraq and Afghanistan wars? Maybe VVAW? (we actually meant IVAW)