Speaker Paul Ryan said Wednesday morning that he stands behind a House Intelligence Committee subpoena to the FBI seeking information on the bureau's handling of the Trump dossier.

Ryan's move is important because Rep. Devin Nunes, chair of the committee, has been weakened by unproven allegations from left-leaning activist groups that he leaked classified information. Last April, Nunes announced he would step aside from playing a public, leading role in the investigation. But he remains chairman, and he signed subpoenas to the FBI, the Justice Department, the opposition research firm Fusion GPS, and Fusion's bank concerning the Trump dossier.

Fusion resisted Nunes' subpoenas partly on the grounds that he had "recused" himself from the investigation (Nunes says he never did) and that therefore the subpoenas were not valid. Other lawmakers believe Nunes' weakness is also part of the FBI's calculation in resisting a dossier-related subpoena from the House committee.

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Nunes subpoenaed the FBI for information on the dossier on Aug. 24. So far the bureau has not provided any information.

That is why Ryan's support is critical. For a House committee's subpoena to have maximum effect, it must have the power of the House of Representatives, in the person of the speaker of the House, behind it.

Which is what Ryan did Wednesday morning. "We've had these document requests with the administration, the FBI in particular, for a long time, and they've been stonewalling," Ryan said in an interview with Reuters. "The FBI and the Justice Department need to give Congress the documents it has been requesting, and they need to do so immediately."

Ryan was particularly unhappy that lawmakers learned the source of the dossier funding last night in a Washington Post report, and not from the FBI itself. "I can't tell you how frustrating it is to learn through the media information that Congress has been requesting from the executive branch for a long time," Ryan said. "So the FBI needs to comply with the document requests that Congress has on their desk right now, and they need to do it immediately."

Finally, Ryan said the FBI's behavior impedes Congress's responsibility to oversee the executive branch. "When the executive branch, in this case, the FBI and the DOJ, are stonewalling or footdragging, that makes it harder for us to do our job of conducting oversight on the executive branch," he said.

Ryan's statements could mark a turning point in the dossier investigation. Until now, at least as far as the House is concerned, Nunes was out there by himself in seeking the FBI dossier documents. Now, he has the most powerful man in the House behind him.