Some parts of the New Deal were declared unconstitutional.
A.L.A. Schechter Poultry Corp. vs. United States: The Supreme Court unanimously ruled against US regulations of the poultry industry. The decision meant that the National Industrial Recovery Act of 1933, a New Deal program, was unconstitutional in the eyes of the court and could not continue.
United States vs. Butler: The Supreme Court ruled that taxes instituted under the Agricultural Adjustment Act of 1933 were unconstitutional, negating another New Deal program.