A three-judge panel of the US Court of Appeals for the Ninth Circuit questioned the Department of Justice (DOJ) on Sunday over its emergency demand that California election officials set aside the mail ballots of roughly 20,000 people the government suspects are non-citizens. After a nearly two-hour hearing, the panel took the matter under submission and has not yet ruled.

The DOJ sued on Oct. 15, claiming that California’s practices are preempted by 18 U.S.C. § 611, which makes it a misdemeanor for a noncitizen to vote in a federal election. When US District Judge David Carter did not rule by the date the DOJ requested, the DOJ sought emergency relief from the Ninth Circuit, even though Carter had scheduled a hearing for Tuesday. Judge Mark Bennett questioned whether the appeals court had jurisdiction to act before Carter ruled.

Bennett also questioned whether the requested injunction could be reconciled with the Elections Clause, which gives states authority over the “Times, Places and Manner” of congressional elections, subject to Congress’s power to alter those rules. He cited Smiley v. Holm, a 1932 Supreme Court decision on states’ Elections Clause power, which DOJ attorney Matthew Donnelly said he was not familiar with.  California has argued that the DOJ’s theory would “turn the Constitution on its head.”

The judges also pressed Donnelly on the reliability of the list. Judge Gabriel Sanchez repeatedly asked which third parties had supplied the government’s data, and said Donnelly’s inability to answer raised questions about the list. California has said the list relies on flawed federal immigration and third-party data. Judge Patrick Bumatay appeared more receptive to the DOJ’s concerns about noncitizen voting, though he also questioned both sides.

Bennett said the panel would try to rule as quickly as possible. More than 3  million ballots have already been cast statewide, according to figures cited in the litigation, and Carter’s hearing remains set for Tuesday.