The Supreme Court is allowing a trial over the decision to add a citizenship question to the 2020 census to go forward over the Trump administration's objection.
The justices' issued a brief order Friday rejecting the administration's request to postpone the trial, set to begin Monday in New York.
Justices Samuel Alito, Neil Gorsuch and Clarence Thomas would have delayed the trial.
A dozen states and big cities, among others, have sued over Commerce Secretary Wilbur Ross' decision to add a citizenship question to the census for the first time since 1950.
The lawsuits argue that Ross acted improperly.
Last week, the justices blocked the questioning of Ross in advance of the trial, but allowed other preparations to continue.