We've run this experiment many times. It has failed routinely. The only way this would work is if the entire point and purpose of the 3rd party was to eliminate the barriers to entry for other parties. Like if it was written into its charter that was the whole point and that once it was accomplished the party would disband. You'd also have to implement a dead-mans-switch to prevent the spoiler effect, something similar to Unity 2020. Good luck getting that to get traction with a plurality when you're fishing in a pond of the disengaged. The other method is to have someone who supports RCV make it to the height of Democratic leadership, but the DNC would never let this happen since it threatens their business model, and the stupid clapping seals that support them will go right along with it.
We have multiple parties, but like Police Academy or Revenge of the Nerds, they stop making sense right around the third one. My imaginary black child will not be trading legalized bath salts cut with fentanyl to pay for grocery deliveries in seat-belt free cars from segregated stores and literacy tutors once "government schools" are shut down and defunded.
I agree with you based on prior history and our system as it has worked for most of our existence as a country. However, the accelerated use of Executive Orders has made a huge circumvention of congress and brought our system much closer to a quasi-presi-mentary system. (If that makes any sense.)
There is a way to reduce the power of the duopoly and increase the likelihood of more parties both running and winning. First-past-the-post vote tabulation, winner-take-all districts, and the primary system all entrench the duopoly and it's harmful to democracy in numerous ways. From rangevoting.org: FPtP is literally the worst possible voting system, other than choosing the winner randomly. One some way to change things for the better is to adopt any voting method other than first-past-the-post. Ranked Choice Voting (aka Instant Runoff or Alternative Vote) is getting a lot of press, but really almost ANY method other than FPtP would reduce or destroy the grip of the duopoly: Condorcet Method, Approval Voting, Score Voting, Ranked Choice Voting. Each of these has it's own disadvantages. I don't think it's possible for the fed govt to pass a law requiring states and municipalities to adopt the same voting system; we can't (and shouldn't) wave a magic wand to just make everyone everywhere use one system. There's still debate about which systems are best in which circumstances. Numerous cities and Alaska have adopted RCV. (Some think that Murkowski (Alaska) was enabled by RCV to take a principled stand after the insurrection; RCV allows her to win by appealing as a second choice to moderate voters, even if the crazies shun her.) We need as many municipalities and states as possible to adopt new voting systems. Here is an excellent interactive explanation of different voting systems: https://ncase.me/ballot/ fairvote.org argues in favor of RCV but there are some critics, like rangevoting.org which argues for Score voting
You underestimate what will happen to the democrats... they will be stuck with neocons and get more war hawkish and conservative. A new party would replace the Republican Party as punishment for betraying Trump. Uniparty v a Patriotic Party that runs on populism.
Here's a possibility, maybe outlandish, but I can dream: Trump make serious noise about creating a new political party (certainly possible.) The GOP panics. Under the current system, a third party splitting the conservative vote will enable democrats to win all but the reddest districts. Progressive politicians, sick of the stranglehold of the democrat party, join with moderate republicans: "Hey, let the crazies go form their own party. Together we will push for reform of voting systems. Are you afraid of losing to a Trump Party nominee in your district? Pass RCV or Approval Voting or Score Voting in your city/district/state ASAP! We'll join with you to make a bipartisan push. Voters hate the entrenched Dem and GOP parties. They hate the duopoly. If we show them a way out, they'll go for it." Progressives, moderate Republicans, and some of the new party all join against the moderate democrats. The marketing is easy: "Tired of being forced to choose between a giant douche and sh*t sandwich? We have a solution!" Moderate conservatives can be confident they'll still win most red districts regardless of third parties. Progressives and far right can campaign on exactly the platforms they want, without fear of handing the election to their polar via the spoiler effect.
