Well, I don’t think a third party will win either to be honest. That’s why I didn’t say it would or that the third party voter should only do so if they can win. I think a strong third party showing like what you described from greens and libertarians from a party that does grassroots organizing like psl would build political power that doesn’t come from the extant local/state bourgeois and national/global bourgeois structures.
That newly built political power would either have its ideas folded into one of the major parties or would fundamentally change the political landscape of the imperial core and become a new major political party or even some unknown third outcome!
I agree with you that voting isn’t gonna turn the government towards leftism of any kind. A leftist third party vote will though tip the scale however imperceptibly towards giving attention, material advantages and public awareness to those ideas.
Now if you’re like me, and you believe that there’s no future with the republicans or democrats, then it’s a no-brainer to vote for a leftist party like psl.
But for a person who sees the ratchet effect in action yet still believes it to be reversible, who believes that the democrats can be good enough to oppose fascism instead of just being its handmaidens, I also believe a third party leftist vote is a no-brainer: it forces the democrats to see your views.
They cant twist your ideas, they can’t say they have a mandate to continue the genocide, they can’t deepfake or dismiss you because you told them in clear, unequivocal terms exactly what votes they could get and in what districts they could win if they had those policies and platforms.
If you don’t care weather we get a new ascendant egalitarian American labor movement that ushers in an end to global neoliberalism or the democrats cynically adopt left wing policies and platforms as long as things get better then a third party vote for the leftist party of your choice is best.