A top House Republican said he was willing to subpoena one of President Donald Trump’s Justice Department appointees to appear before Congress and answer questions about the department’s controversial request to add a question about citizenship to the 2020 census.

Rep. Trey Gowdy (R-S.C.), chairman of the Committee on Oversight and Government Reform, made the comments Tuesday after John Gore, the acting attorney general for civil rights, failed to appear at a committee hearing on preparations for the 2020 census. Gowdy said he was “disappointed, to say the least,” that Gore failed to appear before the committee. He then indicated he was willing to issue a subpoena.

Gore’s testimony is significant because ProPublica reported he was behind the Department of Justice’s request to the Census Bureau to add a citizenship question. In a December letter to the Bureau, the Justice Department requested that the 2020 census add a citizenship question so that the department could better enforce the Voting Rights Act. The Commerce Department, which oversees the Census Bureau, announced in March that it would accept the Justice Department’s request and add the question.

“He’s coming to talk, at some point or another, whether he wants to or not,” Gowdy said of Gore. “I’m happy to issue a subpoena.” He said the panel would convene on May 18 to hear from Gore “whether voluntarily or otherwise.”