In one of the most highly-anticipated cases of the year, the Supreme Court has ruled that the proposed citizenship question for the 2020 U.S. Census will not be added — for now — saying that the administration's explanation for adding it is insufficient.

Writing for the majority, Chief Justice John Roberts said, "[W]e cannot ignore the disconnect between the decision made and the explanation given."

When Commerce Secretary Wilbur Ross, who oversees the Census Bureau, announced he was reinstating the citizenship question in March 2018, he said he was responding to a request from the Justice Department for better citizenship data to assist its enforcement of the landmark Voting Rights Act of 1965. But questions have been raised about that explanation, and Ross has been accused of trying to depress minority responses for political purposes. The court also expressed dissatisfaction with his explanation.

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"If judicial review is to be more than an empty ritual, it must demand something better than the explanation offered for the action taken in this case," Roberts wrote. "In these unusual circumstances, the District Court was warranted in remanding to the agency, and we affirm that disposition."

The federal government maintained that the Justice Department wants the citizenship data to better enforce federal voting-rights laws, but state and local governments, as well as advocacy groups, argued that including the question will lead to an inaccurate count, because it could deter households with minority, undocumented and Hispanic immigrants from responding. These families may fear that the data will be used by the government to target them, though it would be illegal for the government to do so.

Department of Justice spokesperson Kelly Laco said in a statement that the agency as "disappointed " by the Supreme Court's decision on Thursday. "The Department of Justice will continue to defend this Administration's lawful exercises of executive power," Laco added.

Census figures are commonly used by the federal government for congressional apportionment — the process by which seats in the House of Representatives are allocated among states — and to distribute resources and funds to state and local jurisdictions across the country. An undercounting of Hispanics and other minorities could affect states like California, New York, Georgia and Texas, which have large immigrant and black communities.

Emily Tillett contributed to this report.