The House gets a relatively rare chance to directly address the Supreme Court on Tuesday in a legal showdown about whether the Trump administration can add a citizenship question to the 2020 census.

The case is one of the most significant for members of Congress during the current Supreme Court term. The census results determine how many House seats each state gets and affect how states redraw congressional districts. The results are also used to distribute billions of dollars from federal programs that are based on population count to state and local governments.

The House cited those reasons when it asked for time during oral argument. The lawmakers plan to argue that it is up to Congress to ensure an accurate count, and a federal law called the Census Act limits the discretion of Commerce Secretary Wilbur Ross to add a question about whether each person being counted is a citizen.

“The decennial census is a vital cornerstone of our democratic institutions, and none more so than the House of Representatives,” House General Counsel Douglas N. Letter wrote when asking for the time. “The House as a chamber depends upon an accurate census for its institutional integrity, and its membership will be affected by the outcome of this case.”

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