—Kerry Hill, B1Daily

America’s immigration battle is increasingly being fought somewhere other than the southern border.

It is moving into statehouses, courthouses, police departments and federal funding disputes as the Trump administration and several Democratic-led states test the boundaries of one of the oldest tensions in the Constitution: Washington may control immigration policy, but can it force states to help enforce it?

That distinction is producing an expanding collection of lawsuits in 2026. The Justice Department has challenged immigration-related policies in states including New Jersey, New Mexico, Maryland and Illinois, arguing that state restrictions interfere with federal immigration enforcement. States, meanwhile, have challenged federal efforts to condition funding on cooperation with immigration policies or otherwise expand federal enforcement inside their jurisdictions.

The result is becoming something larger than another argument over sanctuary cities.

It is a federalism fight.

Washington Controls Immigration, But States Control Plenty of Other Things

The federal government possesses broad constitutional authority over immigration and removal. States cannot create their own visas, independently decide who may legally immigrate into the United States, or nullify federal immigration law.

But states possess extensive authority over their own governments.

They operate police departments and prisons, administer universities and motor-vehicle agencies, control state property and spend state tax dollars.

That creates the central conflict.

The federal government can enforce federal immigration law. But states argue that this does not automatically mean Washington can require state employees and resources to participate in that enforcement.

The Trump administration, conversely, argues that some state laws go beyond simply refusing assistance and actively obstruct federal officers performing lawful federal duties.

Those two positions are now crashing into each other across the country.

New Jersey Has Become One of the Front Lines

New Jersey offers a particularly vivid example.

The Justice Department sued the state in February over an executive order restricting federal immigration officers’ access to nonpublic areas of state property for civil immigration enforcement without a judicial warrant. The administration argues that the policy unlawfully interferes with federal immigration enforcement. New Jersey has sought dismissal of the case.

Another dispute followed.

The federal government challenged a New Jersey law restricting law-enforcement officers, including federal officers, from concealing their identities with masks in many public interactions and requiring identification in certain circumstances.

That dispute raises a fundamentally different question from whether undocumented immigrants should be deported.

Can a state regulate how federal immigration agents operate while physically inside that state?

The federal government’s position is that states cannot regulate federal officers in ways that interfere with their duties. New Jersey maintains that its laws represent legitimate exercises of state authority.

The courts will have to determine where that boundary lies.

Illinois Is Fighting a Similar Battle

Illinois has become another major testing ground.

The Justice Department sued Illinois over laws that, among other things, create potential civil liability involving federal immigration officers and restrict civil arrests around state courthouses.

Illinois attempted to have that lawsuit dismissed.

In August, a federal court rejected the state’s motion to dismiss, allowing the federal government’s case to continue. Importantly, that ruling did not amount to a final determination that Illinois’ policies are unconstitutional. It means the litigation proceeds.

The disagreement demonstrates why the sanctuary debate has become legally complicated.

A state saying, “Our police will not perform federal immigration enforcement,” presents one constitutional issue.

A state saying, “Federal immigration agents cannot perform certain enforcement activities here,” can present another.

The dividing line between noncooperation and obstruction is becoming one of the central questions of the current immigration fight.

New Mexico Is Testing the Boundary Too

The Justice Department also sued New Mexico and Albuquerque in May.

The federal government challenged provisions restricting state and local agencies from entering agreements to detain people for federal civil immigration violations and limiting the use of public property for immigration detention. The challenged New Mexico legislation also restricts participation in certain federal-local immigration partnerships.

The Justice Department says those policies obstruct federal immigration enforcement.

New Mexico’s policies reflect the opposing view that state and local governments retain authority to decide whether their personnel, facilities and resources will participate in civil immigration enforcement.

Once again, the disagreement isn’t simply about immigration.

It is about who commands local government.

Then There Is the Money

Washington possesses another enormously powerful weapon: federal funding.

The Justice Department recently warned that states could risk billions of dollars in federal welfare funding if state agencies fail to report undocumented immigrants they encounter to the Department of Homeland Security.

The administration’s interpretation expands reporting expectations beyond agencies directly administering certain benefits and could reach other state entities.

The federal government argues that existing federal law supports the requirement.

The threat immediately raises another constitutional issue: How far can Washington use federal money to pressure states into implementing federal policy?

This isn’t an abstract concern.

California and other states have already challenged federal grant conditions tying money to immigration-enforcement requirements. In July, California Attorney General Rob Bonta co-led a coalition challenging conditions attached to billions of dollars in emergency-preparedness grants.

Federal funding is therefore becoming leverage in the immigration power struggle.

Washington doesn’t necessarily need to order a state to cooperate if refusing cooperation becomes financially painful enough.

Whether particular conditions are legally permissible is precisely what courts are being asked to decide.

States Cannot Nullify Federal Immigration Law

There is an important limit on the states’ side.

The Constitution’s Supremacy Clause establishes that valid federal law takes precedence over conflicting state law.

A state therefore cannot simply announce that federal immigration law no longer applies within its borders.

That is why the federal government’s lawsuits frequently argue that sanctuary policies cross from permissible noncooperation into unconstitutional interference.

The Justice Department’s position is straightforward: immigration is principally a federal responsibility, and states cannot enact laws designed to prevent federal officials from carrying out federal statutes.

But federal supremacy doesn’t automatically convert state officials into federal immigration officers.

That distinction is where much of the litigation lives.

California Is Fighting Enforcement Methods as Well

California’s disputes with Washington extend beyond sanctuary policies.

On September 8, California Attorney General Rob Bonta joined an amicus brief challenging alleged warrantless civil immigration arrests. The state argues that federal enforcement practices can disrupt schools, workplaces, healthcare systems and other services administered locally.

California and Santa Clara County have separately sued over development of an ICE facility near Gilroy, arguing that the project violated several federal and state legal requirements. The federal government has been using expanded immigration infrastructure as part of its broader enforcement program.

These cases demonstrate how many points of contact exist between federal immigration authority and state power.

Immigration agents may work for Washington.

But their operations occur on land governed by states, inside communities policed by local departments and around institutions operated by state and municipal governments.

That creates endless opportunities for jurisdictional collision.

Neither Side Has Unlimited Authority

The political rhetoric surrounding immigration frequently makes the dispute sound simpler than it is.

One side may argue that immigration is federal, therefore states must get out of Washington’s way.

The other may argue that states control their own resources, therefore Washington cannot dictate local policy.

Constitutional law makes both propositions more complicated.

The federal government possesses substantial authority to enforce immigration law.

States retain substantial authority over state personnel and resources.

Federal law can preempt conflicting state law.

But constitutional principles also restrict the federal government’s ability to commandeer state governments and simply transform them into administrative extensions of Washington.

The real disputes occur in the murky territory between those principles.

What counts as obstruction?

What counts as legitimate noncooperation?

When does a federal funding condition become coercive?

Can states regulate the conduct of federal agents?

When can federal officers use state-owned facilities?

Those aren’t questions a campaign slogan can resolve.

Courts have to draw the lines.

The Political Map Is Becoming an Immigration Map

The practical result could be increasingly different immigration-enforcement environments depending on where someone lives.

Some states and counties actively cooperate with federal immigration authorities.

Others restrict cooperation, access to government information or use of state facilities.

Washington is now trying to reduce those differences through litigation, funding conditions and federal enforcement.

States resisting the administration are responding with legislation and lawsuits of their own.

That creates an unusual political landscape in which the same federal immigration laws exist nationwide but the relationship between federal agents and local government can change dramatically after crossing a state line.

And that may be the defining immigration conflict of Trump’s second term.

The administration is testing how aggressively Washington can use federal authority to implement a national immigration agenda.

States are testing how aggressively they can use their own sovereignty to refuse participation or regulate what happens within their institutions.

The border between state and federal power is becoming almost as contested as the physical border itself.

—Kerry Hill, B1Daily