What was the primary reason president franklin delano roosevelt had for attempting to "pack the court" in the 1930's?

President Roosevelt tried to "pack the court" because of some reasons. First, several conservative justices were inclined to declare parts of his program the "New Deal" as unconstitutional. Also, h is move to increase the size of the Supreme Court was not permitted by the Congress. Lastly, he was criticized for undermining the independence of the court.