Donald Trump’s unexpected victory has led to a resurgence of interest in federalism on the political left. Liberals hope that constitutional constraints on federal power can protect “sanctuary cities” and other forms of state and local resistance to Trump’s dangerous policies.

NYU law professor Rick Hills, a leading academic expert on federalism, is skeptical of the value of this newfound liberal support for federalism. In his view, many of them have lost credibility because they failed to pay their “federalism insurance premium” when their own party was in power:

Far be it for me, a certified fan of federalism and decentralization, to look a gift horse in the mouth. If Trump’s victory spurs my colleagues to endorse an institutional arrangement the benefits of which are timeless, that is a silver lining to a calamity, even if one suspects that the endorsing of federalism is a little bit opportunistic.

For the rhetoric of federalism to sound convincing, however, one needs to have paid up one’s “federalism insurance premium.” Otherwise, one’s op-ed in favor of those labs o’ democracy, those deciding dissenters, will sound…. about as inspiring as the 1812 Overture played on a kazoo. What do I mean by “federalism insurance premium”? Think of a federal regime as an insurance policy, protecting the risk averse against loss of national power. When one’s Party loses the commanding heights of the federal government, federalism insurance allows that Party to retreat into the provinces as a semi-loyal opposition, a shadow government waiting in the wings, advertising its virtues with Massachusetts Miracles and the Texas Way with Deregulated Housing and so forth. Like all insurance, however, the protection comes at a price: One must pay the “premium” of protecting subnational power when one controls the national government, tolerating subnational experiments that one regards as more Frankenstein than Brandeis.

So here is my question to all those new friends of federalism: Is your federalism insurance premium paid up? For instance, when the Obama Administration was forcing colleges and universities to adhere to federal procedural standards for sexual assault hearings contained in its “Dear Colleague” letter, did you stand up for those subnational institutions’ right to resist coercive Title IX conditions on federal money? No? Then do not be surprised if your pro-federalism rhetoric about the immunity of sanctuary cities to “coercive” conditions falls a little flat.

We pay for constitutional insurance through self-control when we have power, not through rhetoric when we lose it.

Hills is right that one of the benefits of federalism is “insurance” against a federal government that falls under the control of your political enemies. This is far from the only advantage of political decentralization. But it is an important one, nonetheless.

Like Hills, I am also very critical of “fair weather federalists” who support constitutional limits on federal power only when it is politically convenient to do so. Sadly, as he notes, this kind of behavior is all too common on both left and right. I too wish that there were more consistent supporters of enforcing tight limits on federal power. In that happy scenario, we might all be better off than we are now, and it would be easier to resist overreach by Democrats and Republicans alike.

But fair weather federalists’ situational opposition to federal overreach has greater value than Hills suggests. Intellectually, the validity of an argument does not depend on the motives, sincerity, or consistency of those who advance it. In my view, many of the federalism objections to Trump’s likely policies are valid regardless of whether the people making these arguments are being consistent with their own previous views.

Fair weather friends of federalism can also often be valuable allies for more consistent ones. Efforts to enforce constitutional limits on government power almost always involve a coalition of principled advocates and people who only care about the issue when their own ox is the one being gored. For example, many of the most important Supreme Court decisions protecting freedom of speech involved the rights of communists, Nazis, and others whose own commitment to free speech was dubious at best.

As Lord Acton famously put it, “[a]t all times sincere friends of freedom have been rare, and its triumphs have been due to minorities, that have prevailed by associating themselves with auxiliaries whose objects often differed from their own.” The same is true of constitutional federalism. Where it prevails, it is usually by virtue of similar coalitions of convenience. In the same passage, Acton also warned that “this association [with situational allies], which is always dangerous, has sometimes been disastrous, by giving to opponents just grounds of opposition.” Fair enough. But, often, the risk is worth taking, especially when the alternative is near-certain defeat. By allying with fair weather federalists of the left in some cases and their right-wing counterparts in others, consistent federalists can gradually make important incremental progress.

Moreover, situational coalitions can sometimes lead to a more permanent consensus. So it proved over time on issues such as freedom of speech and religion, where groups that started out seeking to protect only their own rights gradually came to accept more general principle that government power in these areas should be strictly limited. In recent years, both liberals and conservatives have learned the painful lesson that they are unlikely to achieve secure, long-term dominance over the federal government anytime soon. Both should realize that they are likely to need a federalism insurance policy in the future. That might make some of them more willing to pay their dues than they were previously.

Be that as it may, sincere advocates of federalism, like Acton’s “sincere friends of liberty,” must be willing to make situational coalitions to further their goals. I argued for enforcing tight constitutional limits on federal power under both Bush and Obama. Today, I am doing it yet again in the face of Trump’s likely policies. And I’m happy to work with anyone who will join me in that cause, regardless of where they might have stood in the past.