David French of National Review Online explains how the Obama administration paved the way for the federal government’s new legal action against California politicians.

American political parties have an enduring and deeply cynical love/hate relationship with federalism. When the opposing party occupies the White House, the Founders’ vision of sovereign states and a limited federal government suddenly has an alluring appeal. Retake the White House, and it becomes time for the states to fall into line.

California progressives have been loving federalism lately. While they’ve pushed through a number of policies specifically designed to fight the Trump administration, few have garnered more headlines than the state’s comprehensive statutory scheme to limit cooperation with federal immigration authorities. The statutes don’t block the federal government from enforcing federal law. They do, however, limit the extent to which federal authorities can depend on California citizens and state officials to affirmatively assist in executing the federal mission.

So that’s federalism, right? While it’s clear that states can’t nullify federal laws, in the absence of conflicting federal statutes, can’t California enact immigration policies that advance its own, unique state interests?

It appears not. Ironically enough, thanks to a determined litigation effort by Obama’s Department of Justice, progressives handed the Trump administration a legal club that will likely beat down California’s attempt to go its own way: A Supreme Court precedent. And … the Trump DOJ picked up that club, suing California to block its new statutes.