The United States House of Representatives has voted 255-67 to hold Attorney General Eric Holder (D) in contempt of Congress for failing to comply with congressional committee subpoenas. Seventeen Democratic representatives joined in the vote for the contempt resolution, while over one hundred protested by walking out of the chamber and refusing to vote.

Holder has refused to turn over certain Department of Justice documents relating to illegal gunrunning operations executed by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (BATFE) between 2006 and 2011. In addition, he has repeatedly provided misleading and inaccurate testimony to congressional investigators, including lying about when he found out about the operation and wrongfully accusing his predecessor of having been briefed on it.

This is the first time in U.S. history that a sitting cabinet-level officer has been held in contempt of Congress, although lower ranking officials—including White House Counsel Harriet Miers and White House Chief of Staff Joshua Bolton under President George W. Bush (R)—have been held in contempt for similar refusals to cooperate with congressional investigations.

The House of Representatives will now refer this matter to U.S. Attorney for the District of Columbia Ronald Machen Jr., who has a duty to investigate and decide whether to bring criminal charges against Holder. Machen, however, is part of Holder’s Justice Department, which presents an obvious conflict of interest. Under normal circumstances Holder would be expected to appoint a special prosecutor instead, but since he is the subject of the resolution this would also present a serious conflict of interest.

It is unclear at this time how these conflicts of interest will be reconciled and whether a criminal investigation will move forward.