On Oct. 4, the House Intelligence Committee subpoenaed Fusion GPS, the opposition research firm at the center of the Trump dossier affair. On Monday, the company told the House what it can do with its subpoena. Fusion GPS chief Glenn Simpson and two others will "invoke their constitutional privileges not to testify," Simpson's lawyers told the committee in a letter. The panel shouldn't even bother to call Simpson to the hearing room, the lawyers said, because he won't answer their questions under any circumstances.

It seems unlikely the House will grant that request. If Simpson and two other GPS officials are going to assert their right against self-incrimination, lawmakers, or at least the majority Republican lawmakers on the committee, will want to hear it first-hand.

What is striking about Fusion's refusal is the form it took. Notifying the House that Simpson and the others will not testify took one paragraph. Yet Fusion sent a 17-page letter to the intelligence committee, going to great lengths to argue that Chairman Devin Nunes is not qualified to issue the subpoena.

"Despite your recusal from the Committee's Russia investigation after falling under scrutiny by the House Ethics Committee, your unilateral issuance of these subpoenas violates your recusal and further undermines the legitimacy of this investigation," the Fusion GPS lawyers wrote. "Nothing within the subpoenas or their attachments provides any indication that the Committee authorized you, as chair, to sign or issue them."

Nunes has noted on several occasions that he did not "recuse" himself from the investigation, but instead "stepped back" from playing a leading public role in the probe. In any event, a subpoena signed by the chairman of a committee — in this case, Nunes — is valid, and a witness's lawyer cannot simply declare it invalid. (Simpson did submit to an interview with Senate investigators but refused to answer their main question, which was who funded the dossier project.)

In any event, Monday's letter went on to lecture Nunes about the committee investigation in a style that could have been written by the committee's ranking Democrat and chief Nunes antagonist, Rep. Adam Schiff. Issuing the subpoena, the Fusion GPS lawyers wrote, "is shameful and reflects a pattern of ultra vires behavior," — that is, behavior beyond Nunes's legal authority, the lawyers wrote.

"Based on this Committee's bad faith interactions with the undersigned counsel and its pattern of unprofessional conduct exhibited during different points throughout this investigation, you have left us with no choice but to advise our clients to assert their privileges in the face of these subpoenas," the lawyers concluded.

The letter asked that Simpson and the others "be excused from appearing for testimony" before the committee.

The letter comes as the House Intelligence Committee is locked in a battle with the FBI over documents related to the dossier. The bureau has let several deadlines pass and has provided nothing to the committee. Now, Fusion GPS is attempting to defy its subpoena in the matter. The list of people who don't want to answer questions about the Trump dossier is growing.