YES THEY ARE ILLEGAL BECAUSE THEY ARE RUINING THE COUNTRY.

> One solution regularly proposed is that the left needs to break with the Democrats and build a third party

Disenfranchised Republicans have spoken this out loud too, but third parties fail in the US because of money. It takes a lot of money to organize enough people to get on all ballots in all jurisdictions. Most Americans otherwise lack sufficient interest to help achieve this.

The other side of the problem is attempts to superficially game the system through artificial candidate selection via primaries and first past the poll voting mechanisms. Once you eliminate those politics does a 180 converting from toxic to exceptionally pleasant.