This attack on state net neutrality is no outlier but one of a series of similar invasions of states’ rights undertaken in the name of corporate sovereignty, which, in the age of a new nationalism, has been elevated above state law. The Trump administration is fighting hard to destroy California’s clean air rules, as if California had no legitimate interest in trying to keep its air clean. Likewise, the Republican judiciary has worked hard to transform the First Amendment into a charter of corporate privileges and immunities that invalidates state laws that would dare elevate matters like consumer privacy over an industry’s marginal revenue.

Everyone knows that federalism arguments are used opportunistically in American politics and that proponents become opponents as soon as they gain control of the federal government. And there is certainly an element of opportunism in what the Trump administration is doing. But there are broader trends at work here, suggesting a deeper shift in what the Republican Party stands for.

“Respect for local authority” and “acceptance of difference” are not themes that inspire the new Republican Party. Instead, as with other angry nationalist movements, it aims to destroy the enemies of the state in pursuit of “greatness,” a project that inherently demands a collectivist mind-set and submission to the party line. The ruthless (and illegal) pummeling of cities that dissent from Trump’s immigration policy is perhaps the most prominent example of what such jackboot anti-federalism looks like.

A declining respect for federalism creates real dangers for the union, by making the nation’s existing polarization even more unbearable. For the states serve as buffers, softening the winner-take-all results of federal elections, and also serve as sanctuaries where people may move to leave behind a politics or a culture they cannot abide. To be sure, the fact that the states often fight political change is what has long propelled a powerful resistance to federalism on the left. But there is more to federalism than racism, for there is an inherent genius in a system that dampens political winds and allows people to vote with their feet as well as their ballots.

This is a giant country, its size more resembling that of an empire than a republic. It always faces the danger of a tyranny of the Electoral College majority, the sense of rule by a distant power, lacking real consent of the governed, destructive of life and liberty. In our times, paradoxically, it is the states, serving as a democratic safety valve, that might just keep the union from falling apart.

Tim Wu (@superwuster) is a law professor at Columbia, the author of the forthcoming book “The Curse of Bigness: Antitrust in the New Gilded Age” and a contributing opinion writer.