Explain why roosevelt was worried about long in the election of 1936?

Roosevelt was worried about Huey Long because Huey Long presented the only real challenge from the left that Roosevelt had ever faced. Long was the ultimate leftist populist leader and attacked Roosevelt doing enough about the poor. Long, however, was assassinated in 1935.

powers  are  denied  to the  national governmentin three distinct ways: some  powers, such as the  power  to levy duties on exports or prohibit the freedom of religion, speech, press, or assembly, are expressly  denied  to the  national government  in the  constitution.