Nothing Democrats can do about it. McConnell will get his 6-3 Supreme Court and even Roberts will not be able to contain the Conservative Court.
Democrats have learned that elections have consequences and what matters most is getting your way, not doing what is right.
So what can Democrats do if they win the White House and Senate in November?
There is much talk about packing the court and expanding seats. But I think that is excessive. What they should do is end the filibuster in the Senate.
Democrats should immediately:
1. Repeal the Trump Tax Cuts
2. Pass effective Gun Control
3. Expand Obamacare and make it impossible to repeal
4. Pass Immigration Reform
5 Pass extensive Environmental Protections
6. Raise the Minimum Wage
Assuming biden wins and the dems take the senate, the first item HAS to be election reform. The fed govt has const authority over FEDERAL elections. It can mandate certain levels of polling places per adult residents. It can mandate polling hours. Perhaps more controversely for the Barrett Court, the feds should be able to mandate how many days after a federal election mailed in ballots can be received and counted.
The feds probably (imo) can't mandate things like voter registration or voter ID, and personally I don't trust the dems on immigration anymore than I truck Moscow Mitch.