WASHINGTON — Attorneys for the American Civil Liberties Union said in a federal court filing Monday night that the Trump administration's one- to two-year timetable for reuniting potentially thousands of separated migrant families shows "a callous disregard for these families and should be rejected."

The ACLU is representing migrant parents who were separated from their families during the "zero tolerance" policy in place last summer, and is also representing children who were separated prior to the policy, when the Trump administration began pilot programs in 2017.

The inspector general for the Department of Health and Human Services estimates that thousands of children were separated prior to zero tolerance, but the government argued that reuniting those children is too onerous. Judge Dana Sabraw of the Southern District of California ordered the Trump administration to begin identifying and reuniting those children anyway, but the Justice Department lawyers have said it will take one to two years.

Attorneys for the ACLU argued in the filing that a list of some of the children separated "very likely exists" because Customs and Border Protection began assigning numbers to track families in April 2018.

"That would immediately reduce the number of cases the government has to review," the ACLU said in the filing.

Further, the ACLU argued, the government's ability to quickly identify the more than 2,800 children separated during May and June 218, under zero tolerance, shows that a two-year timetable to identify children separated from their families as far back as June 2017 is too long.

In a Tuesday afternoon hearing, Sabraw asked for Cmdr. Jonathan White, a top official with Health and Human Services who led the department’s efforts to reunite the separated families, to review the ACLU's filing "as soon as possible."

Sabraw called on members from the plaintiff's team to confer with White in the hopes that a "proposal can be made that is more streamlined and more efficient than the government’s initial proposal."

"This is a very significant issue, obviously, it is as important as the initial reunification and the same care and attention and energy needs to be paid to this second reunification with this class going back to July of 2017," the judge said.

"Both sides have competing proposals, both sides are working for a common good and I think that needs to be emphasized," he said. "The first reunification really was a united effort between two adversaries but they came together .... and did remarkable things in quick order."

White has repeatedly testified that he would have never supported a family separation policy.

The hearing was at times tense, with Department of Justice attorney Scott Stewart taking issue with what he called "the extremeness" of the ACLU's proposals. Stewart also repeatedly criticized what he characterized as a lack of notification of their Monday filing.

Sabraw set the next status conference in the case for next Wednesday.

Justice Department lawyers have stated that they want three months to create a statistical model before reviewing files. The ACLU called that "wholly insufficient given that the entire review of every file can be done within three months."

The ACLU asked Sabraw to order the administration to begin an immediate review of paper files across the three agencies who encountered immigrant parents and children.

"The government should therefore issue an immediate directive to case managers at (Office of Refugee Resettlement) facilities around the country to review their paper files for separations, like the government did in the days immediately following the issuance of the preliminary injunction," the ACLU argued, referring to the injunction by Sabraw that ordered the reunification of families separated under zero tolerance.