Progressives have developed the idea that in the future, when Democrats gain the majority of the US Senate, they may move toward increasing the membership of the Supreme Court, playing hardball as much as the Republicans have under Senate Majority Leader Mitch McConnell.
McConnell refused to allow hearings for Merrick Garland, Barack Obama’s Supreme Court nominee to replace the dead Antonin Scalia, saying it was an election year, and improper to allow an outgoing President to make an appointment.
This was preposterous, as John Adams named John Marshall Chief Justice in 1801, after losing reelection to Thomas Jefferson; Andrew Jackson chose Supreme Court Chief Justice Roger Taney in 1836, his last year in office; and Grover Cleveland, Benjamin Harrison and William Howard Taft chose Justices in their last year in office; and Herbert Hoover chose Benjamin Cardozo in 1932, his last year in office; and Dwight D. Eisenhower chose William Brennan in the year of his reelection campaign; and Ronald Reagan chose Anthony Kennedy in his last year in office in 1988.
We have had differing numbers of justices. up to ten, and there is no constitutional barring of adding more Justices, as Franklin D. Roosevelt wished to do in 1937.
What is good for the goose is good for the gander, as the saying goes, and this might be a way to wield power on the part of the Democrats to create a balanced Court, as otherwise, we will have the most extremist Court since the 1920s!