I thought it was common knowledge that support for Nazis in America was widespread all the way leading to American involvement in WW2.

Here's another sample: http://www.latimes.com/opinion/op-ed/la-oe-ross-nazis-of-los...

What Lewis did not anticipate is that local authorities would prove indifferent to — or supportive of — the Nazis and fascists.

Within weeks of going undercover, Lewis’ network of spies discovered a plot to wrest control of armories in San Francisco, L.A. and San Diego — part of a larger plan to take over local governments and carry out a mass execution of Jews. Lewis immediately informed L.A. Police Chief James Edgar “Two-Gun” Davis of the Nazi scheme to seize weapons and, as Lewis warned in a memo later, to “foster a fascist form of government in the United States.”

Lewis was shocked when Davis interrupted him to defend Hitler. The police chief, he noted in the memo, told him: “Germans could not compete economically with the Jews in Germany and had been forced to take the action they did.” The greatest danger the city faced, Davis insisted, was not from Nazis but from communists living in the heavily Jewish neighborhood of Boyle Heights. As far as Davis was concerned, every communist was a Jew and every Jew a communist.