In the standoff between Texas and the federal government over border control, federal authority wins on paper. The Constitution assigns immigration to Congress, the Supreme Court has treated that authority as exclusive for roughly 150 years, and every Texas attempt to build a parallel state enforcement system has been blocked or struck down in court. What has changed since January 2025 is not the law but the politics: the Trump administration now cooperates with Texas rather than suing it, which lets state forces operate at the border under federal authority without resolving the constitutional question underneath.
Why Both Sides Think They Have the Better Argument
Four constitutional provisions pull in different directions, and which ones you emphasize decides the answer.
The federal case rests on the Supremacy Clause in Article VI, which makes the Constitution and federal laws the “supreme Law of the Land” when state and federal law conflict.1Congress.gov. U.S. Constitution – Article VI Congress has passed the Immigration and Nationality Act, a comprehensive federal scheme covering who may enter, who may stay, and how someone is removed. Decisions about entry and removal also affect foreign relations, which the Constitution places with the national government.
Texas points elsewhere. The Tenth Amendment reserves to the states any powers the Constitution does not hand to the federal government.2Congress.gov. Tenth Amendment Article IV, Section 4 obligates the federal government to protect each state “against Invasion,”3Congress.gov. U.S. Constitution Article IV and Article I, Section 10 bars states from engaging in war unless “actually invaded, or in such imminent Danger as will not admit of delay.”4Congress.gov. Article I Section 10 Read together, Texas argues, a state whose federal partner has failed to stop an invasion has an inherent right to defend itself.
Critics reject the premise. Unauthorized border crossings, they argue, do not meet the constitutional meaning of “invasion,” which historically referred to armed military attacks by foreign nations. The courts have so far declined to treat the invasion clauses as a state override on federal immigration authority.
The Case That Decides Most of This
The rule the courts keep applying was set in 2012, when the Supreme Court decided Arizona v. United States. Arizona’s SB 1070 had, among other things, made it a state crime to lack immigration papers, criminalized unauthorized immigrants seeking work, and let state police arrest anyone they had probable cause to believe was removable. The Court struck down three of the four challenged provisions, holding that Congress has so thoroughly occupied the field of immigration law that even state laws designed to help federal enforcement are preempted if they create independent state authority.5Justia U.S. Supreme Court Center. Arizona v. United States
The one provision that survived allowed state officers to check immigration status during a lawful stop, because that involved consulting federal authorities rather than replacing them. That distinction is the axis every current Texas dispute turns on. A state can work within the federal system. It cannot build its own.
What Texas Has Actually Done
Governor Greg Abbott launched Operation Lone Star in March 2021, deploying Texas National Guard soldiers and Department of Public Safety troopers to the southern border.6Office of the Texas Governor. Operation Lone Star The operation grew from a law enforcement surge into a sustained physical presence, with miles of concertina wire along the Rio Grande, a floating buoy barrier near Eagle Pass, and a state disaster declaration invoked in May 2021 that has kept the operation running across dozens of border counties. Texas has allocated more than $11 billion in state funds to the effort through mid-2025.
The more legally aggressive step was Senate Bill 4, passed in a special session. SB 4 creates two new state crimes. Illegal entry from a foreign nation applies to noncitizens who cross into Texas anywhere other than an official port of entry, starting as a Class B misdemeanor and rising to a state jail felony on a second conviction. Illegal reentry targets noncitizens who return after having been deported, starting as a Class A misdemeanor and rising to a second-degree felony where the person was previously removed after a felony conviction.7Texas Legislature. S.B. 4 – Procedures for Certain Offenses Involving Illegal Entry into This State
The provision that draws the sharpest federal objection is SB 4’s return-order system. A state judge can order someone charged with these offenses to return to the country they crossed from, and on conviction the judge is required to do so. Refusing to comply is itself a second-degree felony.7Texas Legislature. S.B. 4 – Procedures for Certain Offenses Involving Illegal Entry into This State Ordering someone removed from the country has always been an exclusively federal function, tied to diplomatic relationships that only the national government can manage. Mexico has not agreed to accept people returned under state authority.
What the Courts Have Said
The Razor Wire Order
The first clash to reach the Supreme Court came in January 2024, after the Department of Justice sued over concertina wire strung in areas where Border Patrol agents needed access to reach and process migrants. The Court issued a 5-4 order allowing federal agents to cut or remove the wire while the underlying case continued. The order was procedural rather than a ruling on the merits, but it signaled that the Court viewed federal access to the border as the more urgent interest. Texas responded by installing more wire, and 25 other Republican governors publicly backed the state.
SB 4 Blocked, Then Struck Down
SB 4 has never taken effect. The Biden-era Department of Justice, El Paso County, and several immigrant rights organizations sued, and a federal district judge issued a preliminary injunction blocking the entire law. The Fifth Circuit Court of Appeals declined to lift that injunction during the appeal.8Congress.gov. Federal Preemption and Texas S.B. 4
In early July 2025, a three-judge Fifth Circuit panel ruled 2-1 on the merits that SB 4 is unconstitutional. The majority wrote that “for nearly 150 years, the Supreme Court has recognized that the power to control immigration — the entry, admission, and removal of aliens — is exclusively a federal power,” and found that SB 4 strips the federal executive of the discretion in removal decisions that Congress granted to it, not to the states. Unless the full Fifth Circuit agrees to rehear the case or the Supreme Court intervenes, SB 4 cannot be enforced.
How the Trump Administration Changed the Picture
The conflict entered a new phase in January 2025. President Trump issued an executive order titled “Securing Our Borders,” which established a policy of “cooperating fully with State and local law enforcement officials” through federal-state partnerships.9The White House. Securing Our Borders A second order directed the Secretary of Homeland Security to expand agreements authorizing state and local officers to perform immigration enforcement functions under federal supervision.10The White House. Protecting The American People Against Invasion
The practical effects followed quickly. The U.S. Border Patrol Chief deputized more than 300 Texas National Guard soldiers, granting them limited federal authority to make immigration arrests alongside Border Patrol agents.11Office of the Texas Governor. Texas National Guard Soldiers Deputized By U.S. Border Patrol Chief The Trump Department of Justice also dropped its own challenge to SB 4. The civil rights groups that had filed separately continued their litigation, and it was their case that produced the July 2025 ruling striking the law down.
This produces an unusual situation. The federal executive branch now supports what the federal courts say is unconstitutional. Federal cooperation does not resolve the legal question, because the two things operate on different tracks. A state can work alongside federal agents under federal authority all day long, since that fits within the system Congress created. The constitutional problem arises when a state acts independently, making its own arrests for its own immigration crimes and issuing its own removal orders. Federal cooperation and federal preemption can coexist.
Where Control Actually Sits Right Now
On the legal question of who controls the border, the answer has not moved. Immigration enforcement remains exclusively federal. SB 4 is blocked. The Fifth Circuit has now said on the merits that Texas cannot create its own immigration crimes or its own removal system. The razor wire order signaled the same direction on physical barriers that interfere with federal operations.
On the ground, the picture looks different because the federal government has chosen to share the work. Texas National Guard soldiers are enforcing immigration law at the border, but they are doing it under federal deputization, which is the one arrangement Arizona v. United States left open to states. That is why the conflict has quieted without any court reversing itself.
The constitutional question remains open in a practical sense. Federal cooperation is a policy choice that changes with administrations. If a future president reverses course, the same confrontation returns, and the Supreme Court has not yet drawn a definitive line about where federal immigration authority ends and state self-defense begins. Whether Texas petitions the Supreme Court to review the July 2025 ruling, and whether the Court agrees to take it, will determine whether that line gets drawn any time soon.