Obviously, conservative groups viewed the New Deal as a massive violation of property rights as well as an unwarranted intrusion into business. Business leaders objected in particular to Roosevelt's perceived favoritism toward unions, which was put into law by the Wagner Act. Conservative leaders were, however, never able to break Roosevelt's New Deal Coalition, and while their opposition shaped his policies, including the cuts in spending in 1937, they could not stop the thrust of his reform plans.
Other opposition came from the left, and included populists like Huey Long, Charles Coughlin (not exactly a leftist, but did propose radical wealth-redistribution plans) and Francis Townsend, whose plan for a $200 pension for all Americans over the age of 65 helped popularize the concept that would later become Social Security. Basically, these men and the millions who followed them argued that the New Deal had not done enough to achieve economic justice for working class Americans.