There's a very weird tangle between the laws of states (who control how elections are run) and the rules of parties (who can choose candidates, in theory, however they want). Both the GOP and the Democrats have rigged the deck against third parties to keep them from winning, or keeping new ones from blindsiding them — which is part of the serious obstacles that anti-Trump forces face in this discussion.
But the article does miss one major point: the goal of such a contest would not realistically be to win in the November election, but to keep Trump (and Clinton/Sanders) from winning a majority of electoral votes, acting as a "spoiler" for both parties. That's a lot more viable (if still Herculean) goal, since at that point the election moves, under the 12th Amendment, into the House for President and the Senate for Veep, and both of those chambers are controlled by the GOP.
Sorry, Conservatives, It’s Likely Too Late for a Viable Third-Party Candidate
State laws make the GOP’s last chance against Trump nearly impossible.
