“Sanctuary” Jurisdictions: Federal, State, and Local Policies and Related Litigation
Congressional Research Service
Summary
There is no official or agreed-upon definition of what constitutes a “sanctuary” jurisdiction, and
there has been debate as to whether the term applies to particular states and localities. Moreover,
state and local jurisdictions have varied reasons for opting not to cooperate with federal
immigration enforcement efforts, including reasons not necessarily motivated by disagreement
with federal policies, such as concern about potential civil liability or the costs associated with
assisting federal efforts. But traditional sanctuary policies are often described as falling under one
of three categories. First, so-called “don’t enforce” policies generally bar state or local police
from assisting federal immigration authorities. Second, “don’t ask” policies generally bar certain
state or local officials from inquiring into a person’s immigration status. Third, “don’t tell”
policies typically restrict information sharing between state or local law enforcement and federal
immigration authorities.
One legal question relevant to sanctuary policies is the extent to which states, as sovereign
entities, may decline to assist in federal immigration enforcement, and the degree to which the
federal government can stop state measures that undermine federal objectives. The Tenth
Amendment preserves the states’ broad police powers, and states have frequently enacted
measures that, directly or indirectly, address aliens residing in their communities. Under the
doctrine of preemption—derived from the Supremacy Clause—Congress may displace many
state or local laws pertaining to immigration. But not every state or local law touching on
immigration matters is necessarily preempted; the measure must interfere with, or be contrary to,
federal law to be rendered unenforceable. Further, the anti-commandeering doctrine, rooted in the
Constitution's allocation of powers between the federal government and the states, prohibits
Congress from forcing state entities to perform regulatory functions on the federal government's
behalf, including in the context of immigration. A series of Supreme Court cases inform the
boundaries of preemption and the anti-commandeering doctrine, with the Court most recently
opining on the issue in Murphy v. NCAA.
These dueling federal and state interests are front and center in numerous lawsuits challenging
actions taken by the Trump Administration to curb states and localities from implementing
sanctuary-type policies. Notably, Section 9(a) of Executive Order 13768, “Enhancing Public
Safety in the Interior of the United States,” directs the Secretary of Homeland Security and the
Attorney General to withhold federal grants from jurisdictions that willfully refuse to comply
with 8 U.S.C. § 1373—a statute that bars states and localities from prohibiting their employees
from sharing with federal immigration authorities certain immigration-related information. The
executive order further directs the Attorney General to take “appropriate enforcement action”
against jurisdictions that violate Section 1373 or have policies that “prevent or hinder the
enforcement of federal law.” To implement the executive order, the Department of Justice added
new eligibility conditions to the Edward Byrne Memorial Justice Assistance Grant (Byrne JAG)
Program and grants administered by the Justice Department’s Office of Community Oriented
Policing Services (COPS). These conditions tied eligibility to compliance with Section 1373 and
other federal immigration priorities, like granting federal authorities access to state and local
detention facilities housing aliens and giving immigration authorities notice before releasing from
custody an alien wanted for removal.
Several lawsuits were filed challenging the constitutionality of the executive order and new grant
conditions. So far the courts that have reviewed these challenges—principally contending that the
executive order and grant conditions violate the separation of powers and anti-commandeering
principles—generally agree that the Trump Administration acted unconstitutionally. For instance,
the Ninth Circuit Court of Appeals upheld a permanent injunction blocking enforcement of