The justices heard about two hours of arguments in the administration's request to overturn a judge's ruling in favor of Texas and Louisiana that halted U.S. Department of Homeland Security (DHS) guidelines narrowing the scope of those who can be targeted by immigration agents for arrest and deportation.

The court's three liberal members generally signaled support for the administration while the six conservatives appeared more divided, with Justice Samuel Alito embracing the arguments made by the states while others posed tough questions to both sides.

Some of the questions involved whether the guidelines violated immigration law, whether U.S. District Judge Drew Tipton had the power to void the guidelines as he did in June and whether Texas and Louisiana had suffered any significant harm that gave them legal standing to sue.

The guidelines, part of Biden's recalibration of U.S. immigration policy after the hardline approach taken by his Republican predecessor Donald Trump, prioritized apprehending and deporting non-U.S. citizens who pose a threat to national security, public safety or border security.

The two states, whose Republican attorneys general filed the suit, argued that the guidelines ran counter to provisions in federal immigration law that make it mandatory to detain non-U.S. citizens who have been convicted of certain crimes or have final orders of removal. Biden's administration disagreed.

"It's our job to say what the law is, not whether or not it can be possibly implemented or whether there are difficulties there," conservative Chief Justice John Roberts said.

Roberts also labeled as "compelling" the administration's argument that DHS lacks resources to catch and deport all of the roughly 11 million immigrants living in the United States illegally.

"It is impossible for the executive to do what you want them to do, right?" Roberts asked Texas Solicitor General Judd Stone, who was arguing for the two states.

"There are never enough resources - or almost never enough resources - to detain every person who should be detained, arrest every person who should be arrested, prosecute every person who has violated the law," conservative Justice Brett Kavanaugh added.

The justices in July voted 5-4 - with conservative Amy Coney Barrett joining the three liberals in dissent - not to block Tipton's ruling halting the guidelines, announced last year by Homeland Security Secretary Alejandro Mayorkas. Mayorkas cited the longstanding practice of government officials exercising discretion to decide who should be subject to deportation and said that most immigrants subject to deportation "have been contributing members of our communities for years."

Republicans have criticized Biden's administration, saying fewer detentions and deportations have encouraged more illegal border crossings. Kevin McCarthy, the top U.S. House of Representatives Republican, last week called on Mayorkas to step down and said the House may try to impeach him when Republicans formally take control of the chamber in January.

During Biden's first year in office, arrests and deportations of immigrants in the United States illegally declined compared to previous years. In the fiscal year that ended on Sept. 30, 2021, deportations dropped to 59,000 compared with 186,000 the prior year. The administration has attributed the drop to a COVID-19 pandemic-related order used to quickly expel hundreds of thousands of migrants, known as Title 42.

U.S. Solicitor General Elizabeth Prelogar, arguing for the administration, said Texas and Louisiana lack the proper legal standing because they have not suffered direct harm due to the policy. The states have said they would be harmed by having to spend more money on law enforcement and social services due to an increase in non-U.S. citizens present within their borders.

Liberal Justice Elena Kagan told Stone, "We're just going to be in a situation where every administration is confronted by suits by states that can bring a policy to a dead stop by just showing a dollar's worth of costs."

Alito said Prelogar was advocating for "a rule of special hostility to state standing" that would not apply to other litigants such as private individuals.

Some justices also appeared taken aback by Prelogar's argument that federal administrative law does not permit courts to wholly void rules adopted by the executive branch.

Roberts called her view "radical and inconsistent" with longstanding judicial actions throwing out federal agency rules.

"Wow," Roberts added.

A decision is expected by the end of June.