Why was president Franklin d Roosevelt's proposal to add additional justices to the supreme court seen by his opponents as a threat?

Answer 1

Although he presented it as a means to lighten the load on the generally elderly justices, it was widely seen as a transparent attempt to "pack" the court with justices who would support his New Deal programs. Prior to his proposal to add justices to the court, the Supreme Court had struck down several of his programs as unconstitutional, which greatly frustrated FDR. His opponents were quick to seize on his misstep to accuse him of trying to steamroll the court and get around the "checks and balances" provided by the independent Supreme Court.