The biggest incident took place in 1937 when President Roosevelt suggested expanding the Supreme Court by appointing an additional member of the court for every sitting member of court over age 70. In 1937 that would have meant six additional justices being appointed, raising the total number to 15.
In November 1936, Roosevelt won a sweeping re-election victory. In the months following, he proposed to reorganize the federal judiciary by adding a new justice each time a justice reached age 70 and failed to retire. The legislation was unveiled on February 5, 1937, and was the subject of Roosevelt’s ninth Fireside chat on March 9, 1937. He asked, “Can it be said that full justice is achieved when a court is forced by the sheer necessity of its business to decline, without even an explanation, to hear 87% of the cases presented by private litigants?” Publicly denying the president’s statement, Chief Justice Charles Evans Hughes reported, “There is no congestion of cases on our calendar. When we rose March 15 we had heard arguments in cases in which cert has been granted only four weeks before. This gratifying situation has obtained for several years”. Three weeks after the radio address, the Supreme Court published an opinion upholding a Washington state minimum wage law in West Coast Hotel Co. v. Parrish. The 5–4 ruling was the result of the apparently sudden jurisprudential shift by Associate Justice Owen Roberts, who joined with the wing of the bench supportive to the New Deal legislation. Since Roberts had previously ruled against most New Deal legislation, his support here was seen as a result of the political pressure the president was exerting on the court. Some interpreted Roberts’ reversal as an effort to maintain the Court’s judicial independence by alleviating the political pressure to create a court more friendly to the New Deal. This reversal came to be known as “the switch in time that saved nine”; however, recent legal-historical scholarship has called that narrative into question as Roberts’ decision and vote in the Parrish case predated both the public announcement and introduction of the 1937 bill.
Needless to say, the storm of controversy was swift and loud. And even though there was no provision in the Constitution limiting the actual size of the Supreme Court, the fear that this was a political move on the Roosevelt Administration created a huge howl on the part of the Republicans who considered this a power grab on FDR’s part.
So on February 5, 1937 the process was underway. Here is that session of Congress and the arguments which took place.
Just in case you forgot that history very often repeats almost constantly.