The Judicial Procedures Reform Bill of 1937 (frequently called the "court-packing plan") was a legislative initiative proposed by U.S. President Franklin D. Roosevelt to add more justices to the U.S. Supreme Court. Roosevelt's purpose was to obtain favorable rulings regarding New Deal legislation that the court had ruled unconstitutional. The central provision of the bill would have granted the President power to appoint an additional Justice to the U.S. Supreme Court, up to a maximum of six, for every member of the court over the age of 70 years and 6 months.
In the Judiciary Act of 1869 Congress had established that the United States Supreme Court would consist of the Chief Justice and eight associate justices. During Roosevelt's first term the Supreme Court struck down several New Deal measures as being unconstitutional. Roosevelt sought to reverse this by changing the makeup of the court through the appointment of new additional justices who he hoped would rule his legislative initiatives did not exceed the constitutional authority of the government. Since the U.S. Constitution does not define the size of the Supreme Court, Roosevelt pointed out that it was within the power of the Congress to change it. The legislation was viewed by members of both parties as an attempt to stack the court, and was opposed by many Democrats, including Vice President John Nance Garner. The bill came to be known as Roosevelt's "court-packing plan".
If there is one phrase that defines the American Left of today it would be, "an old man in a hurry." And the old ass hippies from the Summer of Love want it all now. Now! Now! Now!
As much trouble as the Left has in facing the obvious, they are cognizant of the fact that they are very unlikely to out live both Bush and Trump's appointees to the High Nine. They would not see the court flipped in their life time and that is intolerable to them.
Therefore the idea of stacking the court when they regain power is gaining real traction among them.
The answer to that is simple. Beat them to the punch now. There is much to be said for a fifteen justice Supreme Court. Right now there is always a huge amount of national anxiety over the replacement of individual justices. That won't be the case if there are fifteen of them.
Admittedly the real answer is to make the office elected rather than appointed. It became a constitutional super-legislature when Blackmum amended the Constitution from the bench. There is no reset button for that under our current system. The constitutional amendment system is completely broken. Both sides have the power of veto over each other and both sides automatically use it.
Now is a good time to do it. The wind is at the president's back. He has built up plenty of politcal capital. The #NeverTrump movement for what it was is now wheezing on life support. He's already built up a more effective legacy than Obama did in eight years. It's time to pour concrete on it. Six justices would do that nicely.