WASHINGTON (Reuters) - The U.S. Supreme Court will decide the fate of a fiercely contested plan by President Donald Trump’s administration to add a citizenship question to the 2020 census, agreeing on Friday to an expedited review of a judge’s ruling blocking the plan.

The justices, in a brief order, granted the administration’s request to hear its appeal of Manhattan-based U.S. District Judge Jesse Furman’s Jan. 15 ruling even before a lower appeals court has considered the matter. Oral arguments will take place in late April, with a ruling due by the end of June.

Furman’s ruling came in lawsuits brought by 18 U.S. states, 15 cities and various civil rights groups challenging the Republican administration’s decision to include the question. The plaintiffs said the question would scare immigrants and Latinos into abstaining from the census, disproportionately affecting Democratic-leaning states.

Furman ruled that Commerce Secretary Wilbur Ross had concealed the true motives for his “arbitrary and capricious” decision to add the citizenship question in violation of federal law.

Opponents have accused the administration of trying to engineer an undercount of the true population and diminish the electoral representation of Democratic-leaning communities in Congress, benefiting Trump’s fellow Republicans. Non-citizens comprise an estimated 7 percent of people living in the United States.

Time is of the essence in the case, as the official census forms are due to be printed in the coming months.

The U.S. Constitution mandates a census every 10 years. The official population count is used in the allocation of seats in the U.S. House of Representatives and the distribution of billions of dollars in federal funds. There has not been a census question about citizenship status since 1950.

Ross announced in March 2018 that the administration would include a citizenship question, saying the Justice Department had requested the data to help enforce the Voting Rights Act that protects eligible voters from discrimination. Only U.S. citizens can vote in federal elections.

Justice Department spokeswoman Kelly Laco said the administration is pleased the justices will review its “legal and reasonable decision to reinstate a citizenship question on the 2020 census.”

The Supreme Court building is seen from the U.S. Capitol in Washington, U.S., February 15, 2019. REUTERS/Joshua Roberts

Trump has pursued hardline policies to limit legal and illegal immigration. On Friday, Trump declared a national emergency in a bid to fund his promised wall along the U.S.-Mexico border without congressional approval, a step he has called necessary to combat illegal immigration.

‘LONG-LASTING EFFECTS’

New York was one of the states suing the administration. New York Attorney General Letitia James, a Democrat, said her office looks forward to defending the lower court victory at the high court, citing the “far-reaching and long-lasting effects” of a census undercount.

American Civil Liberties Union attorney Dale Ho, representing immigrant rights groups suing the administration, said adding a citizenship question would damage democracy. “The evidence presented at trial exposed this was the Trump administration’s plan from the get-go,” Ho said.

The administration has called Furman’s ruling “the first time the judiciary has ever dictated the contents of the decennial census questionnaire.”

In his ruling, Furman said the evidence showed that Ross and his aides “worked hard to generate” a request for the citizenship question from the Justice Department, and that he made the decision despite Census Bureau evidence that such a question would lead to lower response rates for the census.

The judge found a “veritable smorgasbord” of violations of a law called the Administrative Procedure Act.

Democrats call the citizenship question part of a broader Republican effort at the federal and state level, also including voter-suppression measures and redrawing of electoral districts, to diminish the voting power of areas and groups that typically back Democratic candidates, including immigrants, Latinos and African-Americans. Republicans reject the accusation.

A decision by the justices to take up a case like this one before an appeal is handled by one of the regional federal appeals courts is rare. According to the court’s rules, it takes up such requests only when the case is of “imperative public importance” warranting immediate review.

The last time it decided a case officially filed in advance of judgment by an appeals court was in 2005. That case, during the President George W. Bush’s administration, involved a challenge to criminal sentencing guidelines.

The Supreme Court rejected an earlier Trump administration request to halt the New York trial that led to Furman’s later ruling.