I fully support third/fourth/fifth, etc. party options. It forces the STALE mainline two-party system to build broader coalitions and make compromises to govern. My political compass is fairly heterodox, which is why I'm unaffiliated with either D or R. Actually, I'll even go further and say ranked choice voting should be in all 50 states. I think Maine does this for some races, no?
If you get enough seats in Congress that are not mainline D or R, it would force the aforementioned coalition building, not too dissimilar with our friends across the pond. Is this wishful thinking? Probably. Should we implement it? Absolutely!
This is wrong-headed on so many levels. Our two parties already engage in plenty of coalition building and compromise--they just do it through the primary process rather than through post-election parliamentarian maneuvering. Throwing your energies into third-party politics isn't prioritizing coalition building--it's the opposite! It's choosing identity performance over pragmatics and progress.
The two major parties in this country have locked out the competition by creating voting systems that gravitate towards a two-party system. Until this system is ended by the installation of nationwide ranked-choice voting, the Democratic and Republican parties should be considered enemies of "small-d democracy."