Multi-party system allows for more narrow defined political philosophies and cohesiveness of views. While nobody escapes factioning, smaller parties do provide a more uniform voice. During elections people vote for their party, and coalition building starts later. It results sometimes with a smaller party having disproportional influence and sometimes no real voice at all. Coalition building produces a fun spectacle but results in some unstable governments (Italy and Israel, for example, rarely had a government surviving until the next scheduled election).
In US its another way around. Various factions of the major parties go through the bickering infighting process before elections, during the primaries, not after. And its not an orderly negotiation done by the parties' representatives (somewhere in an European smoke room), but looks more like an urban warfare in the heavy fog - sometimes its everybody against everybody.
Of course, its silly to expect a small-party unity on the scale of Republican or Democrat behemoths. I can make a claim that more than 2 parties of a significance are needed (badly!), but we have what we have. It might change eventually, but now we have to work within our reality, regardless that we hate it or not.
It means that a faction needs to build a support base within a larger party and put its people into the offices on different levels. Until you can replace chafees and jeffordses with your own people its better to have them as allies in the larger coalition, even as a shaky allies, than to have them in the opposing camp. If you want the whole coalition to be your own mirror, you have to work long and hard, and still maybe unable to have a half of the country to share on your views.
Like many here, I also have Hunter and Thompson representing my views the best way, and will vote in primaries accordingly, but in November will vote for whoever was left standing on our side.
You’re making an interesting and useful point.
I would submit that the multi-party alternative is more unstable— if not destructive— in the long run. One of the basic weaknesses of democracy in general: a lack of continuity, is exaggerated in its affect. Nobody is in power long enough to do anything for good or ill.