(CNN) A federal judge in New York has struck down the Trump administration's proposal to reintroduce a citizenship question into the 2020 census.

The ruling effectively puts a freeze on a deeply contentious move that critics said would discourage non-citizens from participating in the Census. The Justice Department has said it needed better data on the voting age population to help enforce the Voting Rights Act.

Judge Jesse Furman said Tuesday morning that the proposal is "unlawful," writing that "(Commerce Secretary Wilbur Ross') decision to add a citizenship question to the 2020 Census -- even if it did not violate the Constitution itself -- was unlawful for a multitude of independent reasons and must be set aside."

The Justice Department asked officials to add the citizenship question, saying it needed better data on the voting age population to help enforce the Voting Rights Act. Supporters say this is a common-sense question that simply makes sense to ask.

The administration is likely to appeal the ruling. The Supreme Court has already agreed to hear a portion of the case, saying it will review whether the challengers can introduce evidence outside of the official record, including the testimony of a senior Justice Department official. The court will hear those arguments next month.

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