In theory, all Munich-based military units and thus Hitler’s regiment, too, were part of the Red Army. In that sense, Hitler served in the Red Army. … - Thomas Weber

Hitler himself would imply that he had had Social Democratic leanings in the past when he told some of his fellow National Socialists in 1921, ‘Everybody was a Social Democrat once.’

Being that soldiers, who overwhelmingly had voted for the SPD in the Bavarian elections in January 1919, had elected Hitler as their representative, that Hitler’s closest companion during the revolution had been a member of an SPD-affiliated union; and that the SPD under Erhard Auer had stood against international socialism and cooperated on many an occasion with conservative and centrist groups, one thing is quite clear: Hitler had stood close to the SPD but either had missed the opportunity or lacked the willpower to jump ship after the establishment of the second Soviet Republic.

More important than what I think about Hitler’s performance as a soldier during the war is what the other members of Hitler’s unit thought of him. A letter I found through serendipity in the US National Archives testifies that frontline soldiers in the trenches considered Hitler an Etappenschwein (‘rear area pig’), as they thought that, unlike them, he had landed a cushy job with regimental HQ a few miles behind the front. The reason this is so important is because it puts a lie to the orthodox view that Hitler was a typical product of his wartime unit.