There's a lot of moving parts here to understand
Roe v Wade changed the politics of the court
No matter which side of the aisle you're on Roe v. Wade still looms large in any SCOTUS appointment. Ginsburg's death reiterates that
If Trump is able to install his nominee in that seat, both sides agree there’s a better chance than ever that Roe v. Wade — the 1973 decision established a nationwide right to abortion — could be overturned or gutted.
If there is any court packing to be done, this issue will be front and center, despite the fact that few other politics actually revolve around abortion. Every SCOTUS nominee has faced a Roe related question since Ted Kennedy's Senate speech in 1987 denouncing Robert Bork (who was not confirmed)
Robert Bork's America is a land in which women would be forced into back-alley abortions
This includes all subsequent nominations, except Anthony Kennedy (Kennedy was nominated when Bork withdrew, and was more centrist)
Federal Court appointments have become far more political in general
- Democrats filibustered 10 appellate nominees made by George W Bush. In 2005, with a possible removal of the filibuster for judicial appointments (the Nuclear Option), the Gang of Fourteen got some approvals through and removed the threat
- In 2013, with a desire to fill the three DC Circuit vacancies, Democrats invoked the Nuclear Option on all confirmations save SCOTUS
- In 2017, Republicans invoked the Nuclear Option on SCOTUS confirmations to appoint Gorsuch (after blocking Obama's nomination of Merrick Garland) and later Kavanaugh
It would be Democrats engaged in open court packing
That has always been the rationale, which gained momentum after the partisan Kavanaugh nomination
A right wing court is likely to crush most legislative attempts to steer America down a more progressive and restorative path. Forget single payer health care, transgender rights, criminal justice reform and of course, upholding Roe v. Wade — Kavanaugh and his fellow conservative justices will have the power to shoot those dreams down, no matter what the wider voting public thinks about them.
This forecast might sound like the end of the world to Americans who oppose the Kavanaugh nomination, but in fact, there’s a pretty simple fix that hasn’t yet been seriously discussed in mainstream political forums.
That solution is court packing: that rarest of moments when the president and Congress decide to add seats to the Supreme Court.
In order to pass a law expanding SCOTUS, the Democrats will have to invoke the Nuclear Option one final time against the Legislative process (despite controlling both chambers in 2017, Republicans were loathe to go that far).
Once the filibuster is gone for legislation, Democrats are free to expand the court as they see fit. Since confirmation filibusters are already gone, it would then be a mere formality to nominate new judges of any particular bent and confirm them to SCOTUS. There would be no immediate remedy for Republicans, who would have to wait for a new election cycle. It's unclear how Republicans would handle things once they had a simple majority, but it's entirely possible that if the Democrats expanded SCOTUS by X seats, that they would simply add X seats of their own.