After every lost war, the cheerleaders for it always come up with some stab-in-the-back myth about why the war was lost (these myths are never called “conspiracy theories”). The cheerleaders go on to the next war and those who questioned the war from the get-go generally end up writing articles for obscure websites (like SLL). From Joe Cirincione at responsiblestatecraft.org:
The foreign policy elite are focused on defending their reputations and privileges, not in confronting failure in Afghanistan.
When the Nazi Party consolidated power in Germany in 1933, they enshrined into their version of history the myth that the German Army had not lost in the Great War but had been “stabbed in the back” by cowardly civilian politicians, Jews, communists and socialists.
After maneuvering to get Socialist political leaders to sign the armistice (and, thus, take the blame for it), German General Erich Ludendorff popularized the Dolchstoss Legende. “The lie that German democracy, not the earlier authoritarian regime, was responsible for the disaster of World War I,” writes historian Jeffrey Herf, “figured prominently in the right-wing propaganda assault on the Weimar Republic.” The Nazis then used the lie to paint fascism as a restoration of Germany’s honor and justify persecution of their domestic opponents.
President Richard Nixon and Secretary of State Henry Kissinger created a similar myth to claim that the United States could have won the wars in Vietnam, Cambodia, and Laos had they not been undermined by the antiwar movement, liberals and the press. “The stab-in-the-back theme developed into a full-fledged explanation for American defeat after the war ended,” wrote historian Jeffrey Kimball in 1988, “and as another, related debate unfolded over the causes of failure and the future of policy.”
Years before becoming former President Donald Trump’s national security advisor, H.R. McMaster, wrote an entire book, Dereliction of Duty, using a variant of the concept. He claimed we lost the Indochina wars because weak generals did not stand up to civilian leaders. The “war was lost in Washington, D.C.,” he claimed, barely acknowledging the tenacity and strategy of the Vietnamese.
As Kimball notes, this is not just an effort by the losers of wars to find scapegoats for their defeat. It is part of the struggle to shape future policy. After 9/11, the myth was used to counter the so-called “Vietnam Syndrome” — the twenty years when America turned away from launching major wars — and manipulate a fearful American public into waging a series of new wars in the Middle East.