Besides pathetic insults — or pointing to obvious differences I’ve already acknowledged — so far nobody has spoken to the real similarities and differences of these century-apart challenges to constitutional republican government & democratic norms.
The Weimar Constitution and German “liberal democracy” were attacked not only by Hitler, of course, but also by the then large Communist Party of Germany, which also discredited itself by following every twist and turn of Soviet foreign policy. Most Westerners only recall the Hitler-Stalin Pact of 1939, but that was much later after Hitler was firmly in power and after the Munich Pact.
A more appropriate understanding of the “contribution” of communists to the Nazi takeover in Germany would be discussion of “3rd Period” (1928-1933) ultra left Comintern policy followed by the German CP … which led it to refuse to defend social democrats and democratic socialists and liberal constitutionalists against fascism.
During the “Third Period” — when Hitler was just coming to power —prominent leaders of the Stalinist CP actually assumed Hitler was a passing phenomenon, hat the Social Democrats were rhe “main enemy,” and thought “After Hitler, it will be our turn.” They regretted this foolishness after Hitler came to power and destroyed them completely.
Early on the CP also tried to compete with the Nazis, who much more effectively appealed to powerful nationalist cultural currents in Germany that opposed the French occupation of the Ruhr, and the payment to England and France of reparations for starting WWI.
In short, the CP abandoned an “Enlightened” anti-imperialist and internationalist policy. Of course it is a moot question if it would have made much difference in stopping fascism even had they a radical but rational “democratic socialist” character.
Cursing the chauvinist betrayals of the Social Democratic parties and “Liberals” during WWI, the CP claimed to stand for “working-class revolutionary intransigence” against finance capitalism, and against “bourgeois liberalism,” but of course they were in fact only making the job of the Nazis easier.
The Democratic Party today can not be compared to the Communists of those times. Rather the Democrats are properly compared to the Liberal, or Social Democratic parties of the time, parties that were destroyed by Hitler along with the Weimar Republic and Weimar Constitution.