Good point (that some Democrats want to keep the filibuster rule so as to use it to kill a nominee replacing Ginzberg).
There really is no Constitutional basis for the filibuster. The Constitution only requires a simple majority to approve legislation in each house, and for the Senate to confirm nominees of the President. Overriding a Presidential veto, approving treaties. and recommending changes to the Constitution to the states are the only things the Constitution says require a super-majority.
The Senate, acting like a club, has its rules. The rules are supposed to give each Senator and any large minority of Senators real power to negotiate. When Senators were disposed to making deals, this was fine. It promoted win-win or at least the compensation of losers.
But, the truth is, the filibuster rule was used by the Southern wing of the Democratic Party to prop up segregation. It has an ugly history.
Now that we’re in a time of extreme partisanship, when deals cannot be made, the filibuster rule does little more than allow the dead to rule from the grave.
They really don’t care if their in or out of the Consitutional requirements..it’s all about stopping or slowing down Trump and his administration......not to mention they purposely go outside the lines just to tangle their web tighter and keep the administration wrapped up in legalities.