The American Civil Liberties Union on Friday urged a California federal judge to rule that U.S. immigration officials are illegally separating parents from their children based on criminal histories instead of separating families only when a parent is deemed unfit or a danger to their child, saying its present policy is tantamount to "child abuse."

At a hearing in San Diego federal court, the ACLU pressed U.S. District Judge Dana M. Sabraw to enforce a preliminary injunction barring the separation of immigrant families, while a U.S. Justice Department lawyer said the government needs clarity on when separations can occur. 

"We're talking about permanent trauma to these children for no real reason," Lee Gelernt, counsel for the plaintiffs and deputy director of the ACLU's Immigrants' Rights Project, told the court.

Every child expert and doctor with whom Gelernt has spoken agrees that separation is "basically child abuse, you're terrorizing these little children," he said.

Gelernt urged the court to enforce the preliminary injunction it granted last year, telling Judge Sabraw, "the critical thing is that you clarify that you weren't saying any criminal case can be excluded, and that criteria has to be: 'Is the parent a danger to the child …'"

The guidance issued by immigration officials following the injunction is "written on the assumption that your honor sanctioned them removing anyone with a criminal violation regardless of severity," Gelernt said.

Judge Sabraw said that while "the case law makes clear that, that the application of the Fifth Amendment, the Constitutional right to family integrity, has to be applied according to the circumstances of the case," the court may also need to consider the national security and immigration context in which this case is being heard.

But Gelernt said the context doesn't change the threshold issue.

"You could call any child expert from anywhere in the country and they would tell you these parents are not a danger to the child," Gelernt said.

 The government told the judge it needs clear guidance on the issue.

"If you're going to order that violent felons won't be separated, we need to know that," said Deputy Assistant Attorney General Scott Stewart, representing the government.

Judge Sabraw shared his observation that this is "a very significant issue" and that "criminal history is an obtuse way of determining fitness and danger. But, criminal history has a unique application in the context of this case."

The parents are covered by a class action in California federal court known as Ms. L. v. Immigration and Customs Enforcement, which was filed last year in response to the U.S. Department of Homeland Security's practice of separating families at the border to prosecute and detain the adults.

In June 2018, Judge Sabraw ordered the federal government to reunite all class members with their children, and the government has managed to locate and reunite more than 2,000 separated kids with their parents.

The attorneys for the class later struck a deal, approved by the court, requiring the government to reconsider certain rejected asylum petitions. That settlement agreement also left open the possibility for parents who were already deported to be returned to the U.S. in "rare and unusual" cases.

In March, Judge Sabraw expanded the class to include families who were separated before the administration announced the new enforcement policy, including thousands of children who passed through government custody and had been released at the time of the June 26, 2018, injunction order.

The ACLU said in July. that the Trump administration has separated nearly 1,000 parents and children since Judge Sabraw prohibited it from doing so last year and it is continuing the practice.

A court-appointed steering committee, helmed by the law firm Paul Weiss Rifkind Wharton & Garrison LLP, is working with the government and non-profit partners to locate and reunify parents who have been removed from the country by U.S. immigration officials, but said Friday that despite their efforts, "there are a good number we're not reaching."

The government, represented by Stewart, told Judge Sabraw on Friday that the ACLU has taken an "extreme" and "jaw-dropping" position, pointing to its embrace of a declaration from Martin Guggenheim, an NYU law professor and expert on child welfare and family law.

The Guggenheim declaration, Stewart told the court, "takes the position that a man who rapes a child should not be separated on that grounds. There needs to be a separate determination as to whether that person presents imminent emergency danger to the child."

"It's truly astonishing to me," Stewart said.

But Guggenheim, Gelernt told the judge, was referring to a New York Court of Appeals decision in a statutory rape case. The government, he said, is simply "disagreeing with how this law developed over the last hundred years in every single state."

Representatives for the parties did not immediately respond to requests for comment Friday.

The plaintiffs are represented by Lee Gelernt, Judy Rabinovitz, Anand Balakrishnan, Daniel Galindo, Bardis Vakili, Stephen Kang and Spencer Amdur of the American Civil Liberties Union.

The federal government is represented by Sarah B. Fabian of the DOJ's Office of Immigration Litigation and Deputy Assistant Attorney General Scott Stewart.

The case is Ms. L. et al. v. U.S. Immigration and Customs Enforcement et al., case number 3:18-cv-00428, in the U.S. District Court for the Southern District of California.

--Additional reporting by Nicole Narea and Suzanne Monyak. Editing by Emily Kokoll.