In the latest clash in the U.S. Supreme Court over the Trump administration's travel ban, Hogan Lovells partner Neal Katyal, a former acting U.S. solicitor general, took a dig at Jeffrey Wall, the current holder of that post, over the office's “traditional position” when it comes to taking cases to the justices.

The wonky, yet potentially decisive, skirmish over procedure played out in two footnotes in Hawaii's response—filed by Katyal on Tuesday—to the government's push to more broadly prohibit certain family members, including grandparents, from entering the country from six predominantly Muslim countries. The U.S. Justice Department had earlier asked the justices to reject a Hawaii judge's order that said the government had unfairly blocked the entry of certain family members. Justice Anthony Kennedy may act alone on the government's motion or refer it to the full court.

The flurry of travel ban action stems from the Supreme Court's June 26 unsigned order that allowed parts of the travel ban to take effect. The high court, over the dissent of three justices, said the bans—which targeted immigrants and refugees—only applied to those persons “who lack any bona fide relationship with a person or entity in the United States.”

For individuals, the court said, there must be a “close familial relationship.” As for entities, there must be a relationship that is “formal, documented, formed in the ordinary course, rather than for the purpose of evading [the executive order].”

The Trump administration, implementing the court's modified injunction, moved to exclude grandparents, aunts and uncles, among others, as being “close” family. The government also said the ban applied even to refugees who had a sponsorship-assurance agreement with the U.S.-based refugee resettlement agency.

Hawaii, represented by Katyal, a former acting U.S. solicitor general in the Obama administration, successfully challenged the government's narrow definitions in Hawaii's federal district court. The government on July 14 returned to the Supreme Court.

Wall, the acting solicitor while Noel Francisco awaits a confirmation vote, sought relief through a series of procedural steps—including a motion for clarification of the court's order; or, in the alternative, a writ of certiorari before judgment, of the DOJ's appeal to the U.S. Court of Appeals for the Ninth Circuit; or a writ of mandamus.

Katyal, in his response Tuesday, took on the government's requested relief, charging that it was “procedurally improper and unnecessary.”

The high court, he said, has no rule authorizing the Justice Department's motion to clarify. When the justices have received that type of motion, particularly for substantive motions, they—“and the solicitor general in the past”—have “routinely and summarily” denied them, Katyal wrote.

In a footnote, Katyal contends certiorari before judgment is an extremely rare occurrence and the government's request “is also at odds with the traditional position of the Solicitor General's Office.”

Making his argument, Katyal pointed to a Supreme Court case with which he is intimately familiar, having argued and won it in that court before becoming acting solicitor general: the 2004 decision in Hamdan v. Rumsfeld.

In Hamdan, the solicitor general at the time—Paul Clement, now a Kirkland & Ellis partner—had argued that certiorari before judgment is inappropriate in three situations, Katyal said. “All three of those considerations apply here,” he wrote.

Katyal further said a writ of mandamus—an order to the district court—is unwarranted. The high court's precedents hold that for mandamus to fit, the district court's action must be more than just wrong. The writ is justified only in “exceptional circumstances, amounting to a judicial usurpation of power,” according to a 1980 Supreme Court decision.

“The position of the Office of the Solicitor General here is inconsistent with the prior views of the office,” Katyal wrote in a footnote. “The district court's order is not 'obviously incorrect,' which the government itself has previously viewed as a prerequisite to mandamus review.”

On the merits, Wall argued the government's definition of “close” familial relationships is drawn from federal immigration law. The Hawaii judge's interpretation, he wrote in court papers, “empties the [Supreme] Court's decision of meaning, as it encompasses not just 'close' family members, but virtually all family members. Treating all of these relationships as 'close familial relationship[s]' reads the term 'close' out of the court's decision.”

And a refugee assurance-agreement, Wall tells the court, “does not itself create a relationship between a refugee and a resettlement agency, the government has not treated that fact alone as sufficient to trigger the injunctions. To do so (as the district court did) would render the refugee portion of this court's decision effectively meaningless.”

Katyal countered that the relationship between a refugee and her resettlement agency is formal, documented and formed in the ordinary course. “Just as this court intended, the stay will continue to apply to every foreign national that lacks a bona fide relationship with a person or entity in the United States,” he wrote. “That is no minor outcome: As the government itself acknowledges, some 175,000 refugees currently lack a formal assurance.”

The Supreme Court's order last month letting parts of the ban take effect gave mother-in-law as a clear example of a close familial relationship, Katyal said, defending the district court's exclusion of grandparents, grandchildren, aunts, nieces, and cousins from the travel ban. “If a mother-in-law is 'clearly' within the scope of the injunction's protection, then these relatives must be as well.”