CMV: If the Democrats gain control over the Senate in 2020, the Supreme Court should be expanded to include liberal justices.

The Democrats have been saying for years that if a Republican is elected to the Supreme Court and they are confirmed, then the Democrats will push to expand the number of Supreme Court justices. I feel like if the Democrats do gain control over the Senate and a Republican is confirmed, that the Democrats should push for the Supreme Court to be expanded to include liberal justices. I am not a lawyer or a politician, I just feel like this would be the best course of action if the Democrats gain control over the Senate and a Republican is confirmed to the Supreme Court. I also don't see how the Republicans would be able to stop this.