During the tenure of the non-agression pact, the Communist Party was LEGALIZED in Germany. Hitler HAD to do it because the Communists were then his allies.

The American Left swallowed the inclusion of Hitler's Germany into the Socialist World because they had to for the same reason.

Admittedly, the non-agression pact did lasted longer than many remember (nearly two yearsAugust 23, 1939 - June 22, 1941), and while it was in effect, the Left DID kiss Hitler's ass.

http://www.freerepublic.com/focus/f-news/587544/posts
Never Blame the Left (Were the Nazis Left or Right?)

Hitler's allegiance, even before such sources were known, was acknowledged by socialists outside Germany. Julian Huxley, for example, the pro-Soviet British biologist who later became director-general of UNESCO, accepted Hitler's claim to be a socialist in the early 1930s, though without enthusiasm (indeed, with marked embarrassment).

http://www.us-israel.org/jsource/ww2/molotovpact.html
The Molotov-Ribbentrop Pact

http://www.sciencedaily.com/encyclopedia/molotov_ribbentrop_pact
Molotov-Ribbentrop Pact

http://www.isreview.org/issues/14/Richard_Wright.shtml
Richard Wright: "Using Words As a Weapon"

In September 1939, when Stalin signed the Non-Agression Pact with Hitler's Germany, the Communist Parties switched overnight from Popular Front support for the liberal democracies to a new antiwar line. Many communists around the world were horrified, having spent most of the decade fighting fascism. Wright, however, liked and defended the new line because it coincided with his belief that the US could never fight a war against fascism while it practiced racism at home.

In 1941, Wright traveled around the country for the Party delivering a speech called "Not my people's war" where he argued, "Indeed, the Negro's experience with past wars, his attitude towards the present one, his attitude of chronic distrust, constitute the most incisive and graphic refutation of every idealistic statement made by the war leaders as to the alleged democratic goal and aim of this war."22

Then on June 22, 1941, Hitler broke the pact with Stalin and invaded the Soviet Union. Overnight, the line changed again and the Party became the most patriotic advocate of US entry into the war. Wright agreed to change his position publicly but privately, he felt betrayed. His anger mounted as it became clear that the CP's uncritical support of the US war effort meant they were abandoning the fight against racism. The Party would not tolerate any action that would embarrass the Roosevelt Administration.