Did German voters in 1932 know that voting for the Nazis could lead to war?

Richard J. Evan's The Third Reich Trilogy, and the first book in particular, are an excellent read that would go a long way to answering your question.

But to actually answer your question: Yes, many Germans knew a vote for the Nazis was a vote for war, and this was actually one of the appeals of the Nazi Party for many German voters. Starting a war with Poland to reunite East Prussia with the rest of Germany (so as to make the nation contiguous again) was in fact so popular among German Nationalists that Evans believes that had the Nationalist Party come to power instead of the Nazis that Would War II would have happened anyway.

Many Germans, and those of a Nationalist persuasion in particular, were bitterly angry about the outcome of WWI, and the so called "Stab-In-The-Back" myth was wide spread among this group. Many in this group not only wanted to regain lost territory, but wanted vengeance against the French in particular for the Treat of Versailles. Lebensraum, or "living space", which was the idea of taking over Eastern Europe and repopulating it with germans, while it existed outside of the Nazi Party and Nazi Ideology, was more prevalent with the Nazis than other nationalist groups.

To answer your question about the Social Democrats and Communists: No, both of these parties were internationalist in orientation, the Communists to a much more extreme extent than the Social Democrats. The Social Democrats wished to participate in the League of Nations and uphold the Treaty Of Versailles generally speaking. The Communists transform the Weimar Republic into a worker's state and ally with the U.S.S.R. to promote a global workers movement.

I understand this answer is nowhere near exhaustive, and uses only one source. And I need to stress that I am not a Historian, and there is much more reading and sources out there for you to read, and some will probably be posted here. But I hope this will get you started in the right direction, and I cannot recommend enough Richard Evan's Third Reich Trilogy

Source: Evans, R. J. (2004). The Coming of the Third Reich. New York: Penguin Press.

/r/AskHistorians Thread