(Bloomberg) -- Texas is pursuing a series of legal fights against the federal government that are testing the limits on how far local officials can go to shore up US borders, taking advantage of the concerns over immigration gripping the nation.

The legal machinations are playing out as President Joe Biden and Republican frontrunner Donald Trump visit the Texas-Mexico border Thursday to demonstrate their focus on the issue. Their arrival follows weeks of growing tension in the migration hotspot of Eagle Pass, where state troopers are blocking federal agents from a park along the Rio Grande. 

Texas also recently passed a law that gives local police the right to arrest people who illegally cross the border, a direct threat to the idea that immigration enforcement is outside a state’s purview. But a federal judge on Thursday sided with the Biden administration, blocking the law from taking effect because it would conflict with the “complex and expansive system” Congress created to “regulated entry into and removal from the United States.”

Americans are in a fervor about immigration, roiling the political landscape ahead of the 2024 election. The angst is fanned by Republicans like Texas Governor Greg Abbott who cite a foreign “invasion,” but also by Democratic mayors in Denver, Chicago and New York struggling to cope with the unprecedented influx.

Texas leaders are looking to capitalize on the opportunity. Attorney General Ken Paxton said in an interview with Bloomberg News that the standoff stems from the Biden administration’s refusal to take responsibility for keeping out unauthorized immigrants as well as illegal drugs.

“If the federal government is not going to protect our country, then the states have a right to step up and protect the citizens,” said Paxton, who like all statewide elected officials in Texas is a Republican.

Conservative Majority

The US Supreme Court has long held that the federal government has power over who can come into the country, not states. But a conservative majority on the high court has emboldened Texas to seek to undermine that precedent.

“The state seems intent on testing the limits or changing the existing standard,” said Denise Gilman, a law professor who directs the Immigration Clinic at the University of Texas. “The new composition of the Supreme Court makes it a more viable avenue.”

Read more: Who Polices the Border? The Texas Battle, Explained: QuickTake

Texas has been making a sport of suing the federal government for years. Before he became governor, Abbott was attorney general, and described his job as going into the office in the morning, suing the Obama administration, then going home. Paxton similarly embraces his role as an agitator, championing lawsuits with bombastic press releases that produce favorable coverage in right-wing press. 

Since Biden took office, the state has spent more than $1.4 million litigating dozens of cases related to border security and immigration. The state has also poured billions of dollars into its own security initiatives — using National Guard members and police to monitor border crossings despite lacking explicit authority to enforce immigration law.

Ground Zero

Eagle Pass is ground zero for the confrontation, and Abbott recently announced plans to build an 80-acre camp there to house as many as 2,300 National Guard troops. The city is a major trade corridor into central Texas and a key point of entry for migrants. Trump plans to visit Eagle Pass today as he seeks to keep up pressure over the issue. The president will go to Brownsville, some 300 miles to the south.

Read more: Biden, Trump Set Dueling Visits to US-Mexico Border in Texas

The legal dispute stems from a state effort to string razor wire along the border. The state says the wire deters people trying to enter the country illegally. Federal authorities say it impedes their ability to patrol and aid migrants who may need help, and there have been reports of serious injuries.

Border Patrol agents began cutting the wire, prompting Paxton to sue, arguing illegal destruction of state property. The case is in its early stages, but a preliminary ruling gave clearance for federal agents to remove the wire while the lawsuit proceeds.

Some of the wire is strung along a 47-acre city park along the river, and state officials have blocked Border Patrol agents from entering. Courts have yet to weigh in on whether Texas must allow them access.

Police Powers

The second major states-rights showdown is over a Texas law adopted last year that makes it a crime to cross the border between official ports of entry and allows police to arrest anyone suspected of doing so.

The Biden administration sued, arguing the law usurps federal authority. After the federal judge’s ruling Thursday, Texas is expected to appeal to the Fifth Circuit Court of Appeals, which is already handling challenges from the federal government to an array of Texas border enforcement measures.

Read more: Texas Immigration Law Struck Down by Judge in Win for Biden

“Abbott wants to push the envelope on everything and anything states are able to do,” using the courts to show Texas “is doing everything in its power to block immigration,” said Mark Jones, a political science professor at Rice University in Houston.

While the Constitution doesn’t reference immigration explicitly, court rulings point to specific clauses that give Washington authority over commerce with foreign nations and setting rules of naturalization.

Republicans are hoping the high court will shift more power to states. Under Trump, the court gained a 6-3 conservative super-majority that already has issued opinions granting broader authority to local governments, including ending federal protections for abortion and saying states could set their own rules on the procedure.

The legal push is also tied to shifting national sentiment about the border, as cities thousands of miles from Mexico see a surge of asylum seekers.

Republicans want to keep voters focused on the border because they view it as a winning issue, according to Jones. State leaders are trying to present themselves as taking aggressive action while putting the Biden administration in a tough spot.

“When we talk about Texas engaged in legal battles with a Democratic president, it was always Texas versus the feds,” Jones said. “It has now transformed into a Republican versus Democratic battle.”

--With assistance from Julie Fine and Ryan Autullo.

(Updates to add court ruling in third paragraph.)

©2024 Bloomberg L.P.