^ I agree with this. If the GOP was to splinter, the Democrats would emerge as the "alpha" party. They would essentially take over the position the Republicans had held; they would become the party of the "status quo." For many years, the Democrats have been leaning more and more toward conservatism. This would clinch it for them. But very quickly, a brand new, more liberal- more progressive- party would be formed, to challenge them. What Republicans are left would join the Democrats, while many Democrats would defect to the new party on the left. Nothing would essentially change, except the names of the parties, plus there would be an overall political shift back toward center, to counteract the extreme leaning to the right that's been growing for the last 50-years or so.
But I think the GOP breaking apart is still a pretty big "if" at this point, although their refusal to compromise on anything does rather signal that maybe it's time for them to go.