McALLEN, Texas — A dizzying volley of courtroom maneuvers over a Texas law that would allow the state to arrest and deport people who enter the U.S. illegally sowed confusion at the nation’s border with Mexico on Wednesday as sheriffs, police chiefs and migrants waited for direction.

Texas faced skeptical questioning during a hearing before a three-judge panel of the 5th U.S. Circuit Court of Appeals that ended without a ruling, leaving Texas’ new law on hold for now. It was part of a flurry of activity that included a decision from the U.S. Supreme Court that allowed the law to take effect for several hours Tuesday.

During Wednesday’s hearing, 5th Circuit Chief Judge Priscilla Richman questioned how the state law would be carried out, including how Texas would respond if federal authorities don’t cooperate with a state judge’s order to deport someone.

The U.S. Department of Homeland Security has said it would not have deportation authority under the state law.

“This is uncharted because we don’t have any cases on it,” said Texas Solicitor General Aaron Nielson.

The Justice Department has argued that Texas’ law is a violation of federal authority and will create chaos at the border. Lawyers for the department faced a grilling from Judge Andrew Oldham, who was appointed by Republican President Donald Trump. The third judge on the panel, Judge Irma Ramirez, did not ask questions during the hearing but has previously voted to keep the law on hold.

Richman challenged Texas’ assertion that it is exercising a “core police power,” getting Nielsen to acknowledge that deporting people has been a federal responsibility. But Nielsen denied that Texas is “trying to take over the field” on border enforcement and said the state wants to cooperate with the federal government on what is widely acknowledged to be a crisis.

Nielsen also said he did not know how the law would affect someone who entered the country illegally but came to Texas from another state.

Regardless of how this three-judge panel rules, the legal fight will hardly be over. The 5th Circuit has been considering the state’s appeal of a scathing injunction from a lower court judge that put the law on hold.

The 5th Circuit issued a decision earlier this month that would have allowed the law to take effect, and the Supreme Court essentially declined to intervene Tuesday. But hours after the law took effect, the 5th Circuit reinstated the lower court injunction, pausing the law again.

The Supreme Court did not rule on the merits of the law. It instead kicked back to the lower appeals court a challenge led by the DOJ.

Under the Texas law, once defendants are in custody on illegal entry charges, they can agree to a judge’s order to leave the U.S. or face prosecution. However, Mexico has said it would refuse to take anyone back who is ordered to cross the border.

The impact extends far beyond the Texas border.

Republican legislators wrote the law so that it applies in all of the state’s 254 counties, although Steve McCraw, the director of the Texas Department of Public Safety, has said he expects it will mostly be enforced near the border.

Other GOP-led states are already looking to follow Texas’ path.

In Iowa, the state House gave final approval Tuesday to a bill that would also give its state law enforcement the power to arrest people who are in the U.S. illegally and have previously been denied entry into the country. It goes to Republican Gov. Kim Reynolds. If signed, it would take effect in July.

“The federal government has abdicated its responsibilities and states can and must act,” Iowa state Rep. Steven Holt said.

In Texas, El Paso County Judge Ricardo Samaniego, the top county executive, said immigration enforcement should remain a federal, not state, responsibility, echoing the Biden administration’s view. He said heightened law enforcement presence in the city of El Paso during a previous migrant surge brought high-speed chases and traffic stops based on assumptions that passengers were in the country illegally.

“We got a little glimpse of what would happen if the state begins to control what happens in respect to immigration,” Samaniego said.

Arrests for illegal crossings fell by half in January from a record 250,000 in December, with sharp declines in Texas. Arrests in the Border Patrol’s Del Rio sector, the focus of Abbott’s enforcement, fell 76% from December.

Tucson, Arizona, has been the busiest corridor in recent months, followed by San Diego in January, but reasons for shifts are often dictated by smuggling groups.