And political scientists! (No-one listens to us, of course).
More seriously, the case for standard First-Past-The-Post voting is really bad in terms of its decision-making properties. It's really only as dominant as it is, where it is, because of its historical position. Exactly what you might replace it with is a trickier question, with multiple plausible candidates, all better than FPTP and all different from each other. I lean towards Single Transferable Vote, and its special case AV/IRV in single member elections, but reasonable people can disagree.
Intriguingly, the British Parliament has just effectively used approval voting to try to break its Brexit deadlock. It failed in this case largely because many members voted highly tactically for their 'ideal' option only, not for what they could live with. AV/IRV would have been a better choice, I think, if a compromise winner was actually wanted.
Of course, the simple and well-tested solution is to reduce the power of the Executive, move power to Parliament, and assign power proportionally to parties.
This isn’t true in the U.K., the only country where a third party recently tried electoral reform in a country with FPTP. The Liberal Democrats wanted to get rid of FPTP.
Of course, without skewed vote shares due to FPTP and with a limited choice of realistic coalition partners for a future government, that third party can achieve exactly the same thing through coalition bargaining anyway.
Though there is also some precedent in Canada with previous Conservative party mergers.
That combo will reform our duopoly. Plus other benefits, like improve campaign civility and reduce polarization.
(FWIW, I upvoted you for your end goal.)
I personally don't really care about the political impetus behind changing the election format (not to say I don't care about politics, just that in the case of alternative voting systems the standard US format is almost the worst you could do). Anything that moves the US toward something better would be an improvement.
My one concern is that for whatever reason ranking systems seem to be the thing being pushed most, when approval or rating systems would probably be better.
Changing to an approval system would probably be the easiest way to increase 3rd party viability at the moment. Which of those 3rd parties would benefit is a different issue, but approval systems allow people to diversify their expressed preferences, so at the very least it wouldn't be worse for 3rd party candidates.
The basic issue is that plurality voting is a very poor measure of preference. Imagine if you were asked to measure height of 5 people in the room, 3 of whom are over 6 feet 10 inches tall. You could report how tall they are; this is most similar to a rating system. You could rank order their heights; this preserves rank ordering information but not anything about absolute difference, so the two people who are 7'2" and 7'1" look as different as the people who are 7'2" and 5'2". You could also ask people to just mark which are taller than 6'10", which at least acknowledges that more than one person could be taller than 6'10", and preserves some info about absolute height. Or, you could do as is standard, and just indicate who is tallest, which doesn't preserve much information at all about height.
I'm not opposed to alternate voting systems but I'd like to see one actually increase the power of the underdog(s) in a one party state (the only kind of state where the powers that be feel secure enough to make this kind of change) in the US before I support one. I don't want something that sounds good but furthers the status quo. Political diversity is one of the US's strengths and anything that furthers the status quo is bad for that.
Edit: why is this opinion unacceptable?