In Jennings v. Rodriguez, the Supreme Court is debating the length of detention for immigrants facing deportation. (Olivier Douliery/Getty Images)

The Supreme Court's liberal justices dominated discussion Tuesday about the prolonged detention of immigrants facing deportation, expressing concern about the government holding noncitizens indefinitely without a hearing.

At issue for the court is whether immigrants slated for deportation have the right to a bail hearing and possible release after six months if they are not a flight risk and pose no danger to the public.

The conservative justices were less vocal but expressed skepticism about whether the court should be setting firm deadlines for hearings in immigration cases.

A lawyer for the Justice Department told the high court that noncitizens — whether documented or undocumented immigrants — have no constitutional right to be in the United States.

The justices were taking a second look at the issue after an evenly divided court could not reach a decision last term and scheduled the case for reargument. With Justice Neil M. Gorsuch having joined the bench since then, he could cast the deciding vote.

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The case reached the high court after the U.S. Court of Appeals for the 9th Circuit ruled that immigrants fighting deportation are entitled to bond hearings if they have been held for more than six months. A lawyer for the American Civil Liberties Union, representing a group of noncitizens held for more than a year without a hearing, told the Supreme Court that the outcome of the case will affect thousands of people held in jail-like detention centers.

The outcome takes on heightened significance as President Trump has vowed to broadly increase immigration enforcement across the United States. Immigration arrests are up sharply since he took office in January, but deportations are down this year, in part because of a significant drop in illegal crossings on the southern border with Mexico.

The Supreme Court has previously held that undocumented immigrants are entitled to some form of due process when contesting their detention but also that "brief" detentions were allowed. Courts have interpreted those rulings in different ways, with the San Francisco-based 9th Circuit, for instance, requiring more procedural safeguards for those who would be held for months or even years.

The court's liberals on Tuesday pressed Deputy Solicitor General Malcolm L. Stewart about why immigrants in detention centers are treated differently than criminal defendants, who automatically receive hearings to determine whether they remain locked up pending trial.

Justice Stephen G. Breyer noted that even a criminal suspect accused of "triple ax murders" is entitled to a bail hearing. "That, to me, is a little odd," Breyer said, his voice rising.

Without time limits, Justice Sonia Sotomayor said, noncitizens languish in detention centers, sometimes for years. "That's lawlessness," she said.

During the previous argument last term, Justice Anthony M. Kennedy asserted that the constitutionality of the federal law was not at issue. But on Tuesday, he seemed more sympathetic to arguments in favor of a guaranteed timeline. He asked Stewart whether a lengthy delay because of a shortage of immigration judges was permissible and suggested that there should be a concretedeadline.

"Isn't a bright line rule an easier way?" Kennedy asked.

Justice Elena Kagan followed up and asked whether a five-year backlog, for instance, was allowed. In response, Stewart said, an immigrant fighting deportation could always choose to return to his or her home country.

[Supreme Court considers whether those facing deportation can be held indefinitely]

The six-month deadline that the 9th Circuit set applies to a wide range of immigrants, from people detained after entering the United States for the first time to longtime legal residents. The case was brought by Alejandro Rodriguez, a lawful permanent resident who came to the country as an infant. The Department of Homeland Security started removal proceedings because of a conviction for drug possession and an earlier conviction for joyriding.

Rodriguez, who was working as a dental assistant, was held for three years before he challenged his confinement. The average detention for the others who joined his lawsuit was 13 months.

At oral arguments Monday, Gorsuch questioned the ACLU lawyer about whether federal law prevents the court from hearing such claims and about what would be gained by establishing a bright line rule of six months.

Chief Justice John G. Roberts Jr. and Justice Samuel A. Alito Jr. also seemed skeptical that a firm deadline was the right — or constitutional — approach.

It can be done by Congress or by regulation, Alito said. But, he asked, "Where does it say six months in the Constitution?"

The case is Jennings v. Rodriguez.

Staff writers Maria Sacchetti and Robert Barnes contributed to this report.