Attorney General Jeff Sessions.

Attorney General Jeff Sessions recently announced a new Justice Department policy seeking to pull federal grants from “sanctuary cities” – jurisdictions that refuse to cooperate with some federal efforts to deport undocumented immigrants. Much like President Trump’s earlier executive order targeting sanctuary cities, which was blocked by a federal court decision, the Justice Department’s new policy is unconstitutional. If allowed to proceed, it would create a dangerous precedent for both federalism and separation of powers.

The new DOJ policy would deny federal Edward Byrne Memorial Justice Assistance Grants (approximately $275 million in  2016) to state and local governments unless they meet three conditions:

1. Prove compliance with federal law that bars cities or states from restricting communications between the Department of Homeland Security (DHS) and Immigration and Customs Enforcement (ICE) about the immigration or citizenship status of a person in custody.

2. Allow DHS officials access into any detention facility to determine the immigration status of any aliens being held.

3. Give DHS 48 hours’ notice before a jail or prison releases a person when DHS has sent over a detention request, so the feds can arrange to take custody of the alien after he or she is released.

The first requirement is similar to the demand in Trump’s executive order requiring compliance with 8 U.S.C. Section 1373, the federal law that it references. The two other requirements potentially go beyond that order, though the order was broader in the sense that it applied to a much wider range of federal funds.

The major constitutional problem with all three requirements is exactly the same as the main flaw in the earlier order: Longstanding Supreme Court precedent indicates that only Congress can impose conditions on grants given to states and localities, and that those conditions must be “unambiguously” stated in the text of the law “so that the States can knowingly decide whether or not to accept those funds.” Neither compliance with Section 1373 nor the other two conditions the DOJ seeks to impose are included in the authorizing legislation for the Byrne grants. Sessions and Trump may be at odds on other issues right now. But they are united in their desire to make up new grant conditions and impose them on states and localities after the fact.

Should the administration manage to get away with this, it will set a dangerous precedent that goes far beyond the relatively small Byrne program and the specific issue of sanctuary cities. If the president can unilaterally add new conditions to one federal grant program, he can do the same thing with others. This would give presidents a massive club to coerce state and local governments on a wide range of issues. That power might still be limited by the requirement that conditions be related to the purpose of the grant. But, given the existence of a vast array of federal grants for many different purposes, this would be only a modest constraint.

Some conservatives may cheer when the current administration uses this tool against sanctuary cities. But they are likely to regret their enthusiasm if a liberal Democratic president uses the same tactic to force states to increase gun control, adopt a “common core” curriculum, or pursue liberal policies on transgender bathroom accommodations.

Allowing the executive to impose its own after-the-fact grant conditions also threatens the separation of powers. It goes a long way towards taking control over spending away from Congress and transferring it to the president. This, of course, violates the text of Article I of the Constitution, which clearly gives the power of the purse to the legislature, not the executive.

As conservatives often pointed out during the Obama Administration, the modern executive has already appropriated far too much power that more properly belongs to Congress or the states. It is dangerous to let it seize even more. If the Justice Department proceeds with this policy, hopefully it will be challenged in court, and meet the same fate as the earlier executive order.

The need to prevent the executive from usurping Congress’ spending authority and using it as a tool to coerce states and localities is yet another example of how both left and right can benefit from strong, consistent enforcement of constitutional limits on federal power. If more people learn that lesson, it may be one of the few positive legacies of this otherwise dismal period in American political history.