A federal appeals court will allow a federal judge to further probe whether the Trump administration’s decision to add a citizenship question to the 2020 census was motivated by discriminatory animus, giving civil rights advocates another opportunity to prevent the question from getting on the 2020 survey.

The 2-1 decision comes in a Maryland case challenging the addition of the citizenship question and just days before the U.S. Supreme Court is expected to rule in a separate case whether the Trump administration acted lawfully in adding the question. But the Supreme Court is not considering whether the Trump administration had a discriminatory motive, so the 4th Circuit’s ruling potentially opens up a new pathway to block the question. If any decision does prohibit the question, the government would likely file an emergency appeal to the Supreme Court. The Trump administration took a step to try and avoid that possibility on Tuesday by filing a letter with the Supreme Court, asking it to resolve the claims of racial discrimination when it rules this week.

Census Bureau officials have said they need to have a final decision on the citizenship question by Sunday, June 30, so they can send census forms to the printer on July 1.

U.S. District Judge George Hazel, who is overseeing the Maryland case, blocked the citizenship question earlier this year but did not find the question was motivated by discriminatory intent. Recently discovered files from a GOP redistricting expert showed he may have had a hand in helping get the question on the census. The expert, Thomas Hofeller, previously conducted a study in 2015 arguing that adding a citizenship question to the census would pave the way for redistricting that would benefit Republicans and “non-Hispanic whites.”

The plaintiffs brought Hofeller’s files to the attention of Hazel and asked him to reconsider his ruling. Hazel said earlier this week he would reconsider the evidence if the 4th Circuit allowed him to.

“It is becoming difficult to avoid seeing that which is increasingly clear. As more puzzle pieces are placed on the mat, a disturbing picture of the decisionmakers’ motives takes shape,” he wrote.

The Trump administration said it added a citizenship question so it could better enforce the 1965 Voting Rights Act, but plaintiffs and civil rights groups say that is a lie. They argue the Trump administration’s true motive is to depress the response rate among non-whites in the census, reducing their political power and the amount of federal funds they get.

Circuit Judge James Wynn, one of the judges who voted to allow Hazel to get more information, suggested Hazel consider entering a temporary order blocking the Trump administration from adding the question while he gathers more information.

The Justice Department denies Hofeller’s involvement in adding a citizenship question and strongly denies the question was motivated by discriminatory animus. In a letter to the Supreme Court on Tuesday before the 4th Circuit’s decision, Solicitor General Noel Francisco said the plaintiffs’ request in the Maryland case “is based on a speculative conspiracy theory that is unsupported by the evidence and legally irrelevant to demonstrating that Secretary Ross acted with a discriminatory intent.”