A panel of federal appeals court judges late Tuesday continued to block Texas from arresting and jailing migrants under a contentious state immigration law known as SB4, keeping a hold on the measure while it weighs its legality.

In a 2-1 decision, the panel of 5th Circuit Court of Appeals judges denied Texas’ request to suspend the lower court order that found SB4 unconstitutional and in conflict with federal immigration laws.

Pending further court action, Texas will continue to be prohibited from enforcing SB4, which would criminalize unauthorized immigration at the state level. The 5th Circuit has a hearing next week, on April 3, to consider the question of whether SB4 is lawful and constitutional.

Texas is defending SB4 from legal challenges filed by the Justice Department and two groups that advocate on behalf of migrants.

Passed by the Texas legislature last year, SB4 would create state crimes for entering or reentering the state from Mexico outside an official port of entry. These actions are already illegal under federal law.

Law enforcement officials, at the state, county and local level, would be authorized to stop, jail and prosecute migrants suspected of violating these new state criminal statutes. SB4 would also allow state judges to order migrants to return to Mexico as an alternative to continuing their prosecution.

Texas officials, including Gov. Greg Abbott, have touted the strict law as a necessary tool to combat illegal immigration. Accusing the Biden administration of not doing enough to deter migrants from coming to the U.S. illegally, Abbott has mounted an aggressive state border operation, busing tens of thousands of migrants to major cities and fortifying areas near the Rio Grande with razor wire, barriers and National Guard troops.

But SB4 has garnered withering criticism from migrant advocates, the Biden administration and the Mexican government, which has denounced the Texas law as “anti-immigrant” and vowed to reject migrants returned by the state.

In its lawsuit against SB4, the Biden administration has argued the state measure jeopardizes diplomatic relations with Mexico, ignores U.S. asylum law and obstructs immigration enforcement, a longstanding federal responsibility.

Two judges on the 5th Circuit panel appeared to agree with the Biden administration’s arguments.

“For nearly 150 years, the Supreme Court has held that the power to control immigration—the entry, admission, and removal of noncitizens—is exclusively a federal power,” Chief 5th Circuit Judge Priscilla Richman wrote in the majority opinion on Tuesday. 

“Despite this fundamental axiom, S. B. 4 creates separate, distinct state criminal offenses and related procedures regarding unauthorized entry of noncitizens into Texas from outside the country and their removal,” she added.

Camilo Montoya-Galvez

Camilo Montoya-Galvez is the immigration reporter at CBS News. Based in Washington, he covers immigration policy and politics.