Existential self-defense/doom aversion has replaced governing agendas as the bipartisan election strategy. And it's on these terms that coalitions are now formed as well as mobilized. This is deeply endogenous to the constitutional dysfunction of the US.

Since the 1990s, it's been clear that "winners" don't get to govern. Lived experience increasingly makes legislative agendas feel hollow, while existential threat is at least amply understood to be real. The shift in marketing strategy was almost unavoidable.

And the fragmented, anti-majoritarian features of the Constitution make it possible for both sides to understand themselves as both natural political majorities and endangered political minorities--ever-renewing the sense of threat, & the promise of safety.

This is, among other things, a dynamic likely to super-empower the Supreme Court, which basically has constituencies inasmuch as various parts of the polity fear one another.

The Sanders-Warren policy primary is the obvious counterexample. It was a response to the manifest need to legislate a different world, plus the grasp that only politics can do that. But it was rejected, by people who liked the proposals, as otherworldly.