The Constitution does not fix the Court's size, and Congress changed it several times before 1869, often for political advantage. In 1937 Franklin Roosevelt openly tried to add up to six Justices. The plan collapsed amid backlash from his own party, yet the Court shifted anyway, the so-called 'switch in time that saved nine.'
Historians dispute whether the plan caused the Court's shift, since Roberts voted to uphold the Washington law in December 1936, before it was announced. Whether FDR won or lost, and whether 1937 set a lasting norm against court-packing, is also argued.



