New York Attorney General Barbara Underwood is asking a federal judge to compel U.S. Commerce Secretary Wilbur Ross to appear for a deposition as part of her lawsuit over his agency’s decision to ask about citizenship on the national census in 2020.

In a filing late Monday, Underwood’s office said the Trump administration has so far been unwilling to make Ross available for a deposition and that information potentially gleaned from his testimony cannot be obtained elsewhere.