"Of course, it is possible that recent liberal praise for constitutional constraints on federal power will prove to be an example of 'fair-weather federalism'..."

"... the tendency of both left and right to rely on federalism whenever their opponents control the White House, only to jettison it when they themselves are in power. Conservatives, for instance, used constitutional federalism as a tool against the Obama administration but often ignore it under Trump. But there may be a trend here that goes beyond short-term partisanship. Liberals and conservatives alike can benefit from stronger constraints on federal power. Each party can gain from protecting local diversity and experimentation, and from the insurance federalism provides in times when its opponent hold the reins of power in Washington. Left and right can agree on the need for substantial constitutional limits on federal power, even if they differ on exactly how tight those limits should be."

Writes Ilya Somin in "How liberals learned to love federalism/The left was skeptical of giving power to the states. Until the Trump era" (WaPo).

This is the subject I wrote about for 30 years when I was in the law professor game.