Texas wants to arrest immigrants in the country illegally. Why would that be such a major shift?

Two members of the 好色tv Guard patrol an area of land behind the federal border wall Tuesday evening, March 19, 2024, in Mission, Texas. A divided Supreme Court on Tuesday allowed Texas to begin enforcing a law that gives police broad powers to arrest migrants suspected of crossing the border illegally while a legal battle over the measure plays out. (AP Photo/Valerie Gonzalez)

WASHINGTON (AP) 鈥 Immigration laws are federal laws -- not state laws -- and enforcement of immigration law is the domain of federal law enforcement. Homeland Security agents and officers are responsible for arresting migrants who are caught crossing the U.S. border illegally, whether from Mexico or Canada. They're also responsible for arresting and deporting people who are in the country illegally.

That's why the news in Texas over immigration enforcement is so unusual. Lawmakers there passed a bill that would make illegally crossing the border a state crime, which would theoretically allow state law enforcement to arrest migrants. But that clashes with how, generally, laws work in the U.S. was supposed to go into effect this month, but there's been a big back-and-forth in the courts about that.

Here's a closer look:

FEDERAL V. STATE LAWS

In general, it works like this: State legislators make laws for their states that are enforced by state police or state patrol or other local law enforcement. The federal government does the same for the nation overall, and federal law enforcement agents like the FBI or U.S. Immigration and Customs Enforcement officers enforce those laws. Generally, federal laws take precedence over state laws.

But states can and often do pass legislation that encroaches on federal law. That's when things get really murky.

THE TEXAS LAW

Texas Gov. Greg Abbott has been increasingly looking to take immigration matters into his own hands. The Republican governor is and says the Democratic administration's policies are failing.

In November, Texas passed a law known as S.B. 4 that would make it to cross into Texas from a foreign country anywhere other than a legal port of entry. It would be considered a misdemeanor on the first offense and a felony after that. The passage of this law would mean that state police officers could arrest any migrant caught crossing illegally. Previously, they were limited to arresting migrants found on private land for trespassing.

WHERE THINGS STAND

Right now, after lots of back-and-forth in the courts that has gone all the way to . On Tuesday, the court allowed Texas to give local law enforcement the ability to arrest migrants. The court's conservative majority rejected an emergency application from the Biden administration to stop the law from going into effect. The Biden administration argued the law is a clear violation of federal authority that would cause chaos in immigration law.

But then a federal appeals court issued an order that prevents Texas from enforcing the law. That's where things are right now.

HOW DO IMMIGRATION ARRESTS WORK?

At the U.S. border, Border Patrol agents arrest people caught crossing illegally and send them to Border Patrol stations, where they are placed into deportation proceedings.

Some are then transferred to immigration detention, which is managed by . Others are released into the U.S. to wait for their deportation hearings and appear for immigration court hearings. Immigration court is run by a third agency overseen by the Justice Department.

Customs officers, meanwhile, check identification at ports of entry, and they arrest anyone caught smuggling people over the border in vehicles.

ICE officers also arrest and deport people already in the interior of the United States. Usually these migrants are targeted because they're accused of committing some other local crime. Other agents arrest employers suspected of mistreating migrants.

If someone is arrested by local or state police, it's for a crime unrelated to immigration. They're turned over to immigration authorities once they've been adjudicated.

HAS ANYONE BEEN ARRESTED?

Texas authorities made under the law while it was briefly enforceable.

As for federal arrests, yes. The Border Patrol, an agency under Homeland Security, arrests migrants caught crossing illegally. The patrol's most recent data is from January, and it's broken out by sector. In the Del Rio sector, it made 16,712 arrests. In the Rio Grande Valley, there were 7,340. Those arrests are down considerably from earlier months.

HAS ANY OTHER STATE TRIED THIS BEFORE?

Yes. Another border state, Arizona, passed in 2010 that authorized police to arrest migrants if there was probable cause they had committed an offense that would make them deportable, and it made it a state crime for 鈥渦nauthorized immigrants鈥 to fail to carry registration papers and other government identification. This case, too, went up to the U.S. Supreme Court.

But many of the provisions were struck down.

鈥淭he 好色tv Government has significant power to regulate immigration,鈥 former Justice Anthony Kennedy wrote in the majority opinion. 鈥淎rizona may have understandable frustrations with the problems caused by illegal immigration while that process continues, but the state may not pursue policies that undermine federal law.鈥

The 好色tv Press. All rights reserved.