The Supreme Court will let President Donald Trump try to reshape how the country divides up congressional seats, tossing Friday a challenge to his effort to exclude undocumented immigrants from the process.

The high court did not rule on the legality of Trump’s effort, only that the litigants could not bring the case now. The president’s victory is essentially a punt — setting up another case down the road if Trump could actually enact the policy before leaving office.

The six conservative justices voted together after questioning during oral arguments the practicality of ruling before the census results are finished being processed.

“At present, this case is riddled with contingencies and speculation that impede judicial review,” the unsigned ruling said.

Trump and his allies have argued that including undocumented immigrants in census figures used to reallocate congressional seats dilutes the power of voters in states with few immigrants. An estimate from the Pew Research Center said the effort could shift as many as half a dozen congressional seats among the states.

The three liberal justices dissented, arguing the court should have ruled the effort unconstitutional. Justice Stephen G. Breyer wrote that the majority’s decision “risks needless and costly delays in apportionment.”

“Where, as here, the government acknowledges it is working to achieve an allegedly illegal goal, this court should not decline to resolve the case simply because the government speculates that it might not fully succeed,” Breyer wrote.

It’s unclear, though, how many undocumented immigrants Trump can exclude or whether he could actually accomplish his goal. The administration has not said how many undocumented immigrants it can definitively identify within census responses — their attorneys have told the courts it could be in the tens of thousands rather than the millions.

Additionally, the Census Bureau has identified problems with more than 900,000 records, according to documents leaked earlier this month to the House Oversight and Reform Committee. To address those issues, the agency may have to delay delivery of apportionment data until after Trump leaves the White House on Jan. 20.

[House Oversight panel subpoenas Wilbur Ross for census records]

The issue could head back to the Supreme Court next year as the memorandum could cost states like New York and California seats in Congress. Dale Ho, director of the ACLU’s Voting Rights Project and one of the plaintiffs said Friday the group would sue next year if Trump carries out the plan.

“This ruling does not authorize President Trump’s goal of excluding undocumented immigrants from the census count used to apportion the House of Representatives. The legal mandate is clear — every single person counts in the census, and every single person is represented in Congress. If this policy is ever actually implemented, we’ll be right back in court challenging it,” Ho said in a statement Friday.

Justice Department spokeswoman Mollie Timmons said in a statement: “We are pleased that today’s ruling clears the way for the Commerce Department to continue its work on the census and send its full tabulation to the President.”

Trump signed the memorandum seeking to exclude undocumented immigrants in July. Shortly after that, the administration dropped efforts to extend the census count so Trump could still control apportionment calculations regardless of who won the November election.

Several states and civil rights groups filed suit over Trump’s memorandum, resulting in lower court decisions against the administration.

Three panels of federal judges ruled against the administration, finding the memorandum violated federal law on the census or the Constitution. However one panel of judges based in Washington, D.C., ruled the case to be premature.

About 10 million undocumented immigrants live in the United States, according to a 2016 estimate by Pew Research Center. Most of them are concentrated in large states like California, Texas, Florida and New York. The Pew estimates also noted Nevada as having the highest percentage of undocumented immigrants at 7 percent. Vermont had the lowest undocumented population, at about 0.1 percent of the state.

However, the administration has not said how many undocumented immigrants it could cross-reference with census results and exclude. Justice Department attorneys have said the group could be as small as several thousand currently in immigration detention or up to several million, including Deferred Action for Childhood Arrivals recipients.

House Oversight and Reform Chairwoman Carolyn B. Maloney, D-N.Y., criticized the decision, accusing the Trump administration of withholding information for the sake of a favorable ruling.

“This lack of information about the Census is a problem of Secretary Ross’s own making—and it applies not only to the Trump Administration’s plans for undocumented immigrants, but also to the accuracy, completeness, and timing of the entire Census itself,” Maloney said in a statement Friday.

The administration has pushed to execute that plan before losing control of the apportionment process when President-elect Joe Biden takes office on Jan. 20.

Census results are also used in legislative map making, guiding $1.5 trillion in federal spending each year and thousands of private business decisions.