The department has previously signaled openness to prosecuting contempt of Congress under certain conditions. In a 2015 letter to Congress in a different contempt referral, the Justice Department said its position on the matter was that “in appropriate circumstances, a United States Attorney’s Office will refer to a grand jury […] witnesses who contumaciously withhold testimony or other information that Congress has legitimately sought.”

The committee’s efforts have exposed how powerless the modern Congress is without support from the courts or the Justice Department when witnesses or presidential administrations refuse to comply. During the 1950s investigations into domestic communist activity or in the wake of the Watergate scandal, Congress exercised considerable power in conducting investigations. But today, that power has ebbed in response to pushback from the executive branch, partisan divisions within the legislature, and open defiance from witnesses in a number of high-profile matters.

“At a high level, it raises fundamental questions about the power of Congress to investigate,” said Carl Tobias, a law professor at the University of Richmond School of Law.

Disputes over what Congress has the power to demand are nearly as old as the republic itself; George Washington’s administration tangled with a special investigative committee probing an ill-fated military expedition in 1792. But in recent decades, reluctant witnesses and presidential administrations playing hardball have shown there is little penalty for defying Capitol Hill—and few tools available for Congress to force compliance.