With that said, before you start writing your state legislature about “Multi-member districts TODAY!” you should also know that they have a very difficult history of being shot down by the Supreme Court. This was pointed out to me by a number of good folks on Politics.StackExchange[1].

But yes, the route to avoiding a second US Civil War is only incidentally through the “eliminating gerrymandering” nodes of the graph—the 50/50 saturation of the vote into two spineless political parties happens in both the House (gerrymandered to hell) and the Senate (not gerrymandered at all) and is a consequence of something more fundamental. States do need to switch to the proportional system, but there is a decent chance that the Supreme Court might destroy this out-of-hand, in which case a Constitutional amendment may well be necessary.

[1] “Would Switching to a Proportionate House Require a Constitutional Amendment?” https://politics.stackexchange.com/questions/42551/would-swi...