It has now been more than a month since a House Intelligence Committee subpoena set a September 1 deadline for the FBI and the Justice Department to turn over documents related to the Trump dossier.

Not a single document has been produced. The first deadline was extended once, then again, then again, and is now on some sort of hold. But no documents have been handed over.

Deputy Attorney General Rod Rosenstein met with committee chairman Devin Nunes last Thursday -- the committee can perhaps take comfort in the fact that it is being put off by progressively higher-ranking officials -- but it is not clear if the committee is any closer to receiving the documents than when it first issued its subpoena on August 24.

Also on Thursday, Rosenstein met with Senate Judiciary Committee chairman Charles Grassley, who is also pursuing testimony and documents about the dossier and other matters. Grassley and the Justice Department have been going back and forth about Grassley's requests to interview two FBI officials, James Rybicki, who was former director James Comey's chief of staff, and Carl Ghattas, who heads the FBI's national security branch.

Just as they have been doing with the House intelligence panel, the FBI and Justice Department tried to blow off Grassley, saying any talks with Rybicki and Ghattas might interfere with the investigation of special counsel Robert Mueller. Then, after Grassley threatened to subpoena the two officials, the Justice Department wrote back to Grassley on September 22 to say, "Upon further evaluation, we believe that it is appropriate to make Mr. Ghattas and Mr. Rybicki available to the committee for interviews."

But Justice still had conditions, particularly where the Mueller investigation was concerned. So in a letter last week, Grassley reminded them that, "contrary to the implication [from the Justice Department], the committee had, in fact notified and consulted with special counsel Mueller's office for deconfliction purposes about interviewing these two witnesses. Specifically, the committee provided ample opportunity for that office to voice any objection, and accommodated that office's concern…" In other words, Grassley said, Mueller's office did not voice any concern about the committee's request.

Of course, Grassley is so far just threatening a subpoena. The House committee had already issued one. And in both cases, the FBI and Justice Department have not produced either the dossier documents or the two FBI officials (who are thought to know quite a bit about the dossier).

Investigators in both House and Senate are serious about wanting to know the dossier story. They want to know why the FBI would have taken up, during the height of last year's presidential campaign, an opposition research project in which a former British spy, paid by supporters of Hillary Clinton, collected what Comey called "salacious and unverified" allegations about Donald Trump and Russia. Grassley said the episode raised "questions about the FBI's independence from politics."

Now, the FBI and the Justice Department are resisting Congress's effort to understand what the bureau did in the 2016 campaign. It seems clear that if it were up to the FBI, the public would never know what went on in the dossier affair. Which means that right now, the House and Senate are the public's only chance.