I think you misunderstand the spoiler effect. It's working as designed.

The problem is how we vote, not who is on the ballot. As long as the winner is going to be the one with the most votes, then more contenders will mean the winner will have a smaller overall share.

The margin in Florida for the 2000 election was so small that if half of the Nader voters voted for Gore, Gore would've been the clear winner of the state and thus the country. Both left-leaning, environmentalist candidates.

But, like you, they let good be the enemy of perfect, and incidently got us Bush, who was (checks notes) much worse for the environment.

Third parties, in this system, only serve as tools of the opposing major political party. They are absolutely worthless for any progress at the federal level. Do you think a green president could actually get anything done without a green coalition in congress, or among Governors?

There are only three paths for third parties to ascend:

• We change the voting system, get rid of FPTP, or
• Third party builds momentum in lower offices, or
• One of the established parties completely implodes upon itself. See also Whigs, Democratic-Republicans, Federalists.

Bravo, ideologically. Functionally, boo.