Here's the best argument for expanding & thereby repairing the Supreme Court. Over the past 2 decades, starting with Bush v. Gore, the court's conservative majority has pursued an aggressive agenda to keep Republicans in power & Republicans in turn appointed conservative justices

This has skewed our political system & improperly increased the number of conservative justices. Those justices have skewed the system to preserve GOP control in Tuesday's Census decision, Citizens United & Shelby County v. Holder (overturning Sec. 5 of the Voting Rights Act) AND

in Gill v. Whitford (upholds outrageous GOP gerrymandering in Wisconsin) and in cases upholding strict voter ID laws & other partisan GOP maneuvers.

There's a strong argument that the GOP has improperly gotten three SCOTUS seats that should have gone to Democratic appointees.

Bush v. Gore was essentially a 5-4 judicial coup that awarded the presidency to George W. Bush. Bush appointed two justices (Roberts & Alito) & if Gore had been president for Bush's two terms, those vacancies would have been filled by Democratic appointees

Republicans stole a seat by not considering Merrick Garland. So there's a strong case that GOP presidents filled 3 vacancies that Democrats should have filled. This created today's 5-4 conservative majority when there'd be a 7-2 liberal majority if Democrats filled those seats.