You missed my point. By saying “third party”, he still regards the Democrats and Republicans as separate entities ideologically.
As for alleged legalities, that’s akin to regarding the Supreme Court’s kritocratic social moves of late as “legal”.
I didn’t miss your point. I think your point is irrelevant to the issue of whether you think we need a new party. Whether you count them separately or just as one, the core issue is do we need another party (whether you count that as no. 2 or no. 3), or not?