Same winter, same subject, two official objects. Only one became the thing later histories treat as "how the United States learned."
The Senate's Church Committee (S. Res. 21, 27 January 1975) published its final report on 29 April 1976. The Senate then passed S. Res. 400 on 19 May, 72–22, and created the Select Committee on Intelligence. FISA followed as Public Law 95-511 on 25 October 1978, with a court that had to see a warrant request. That chain has a statute, an anniversary, and a committee that still sits.
The House Select Committee under Otis Pike voted 9–4 to release its 338-page report. On 29 January 1976 the full House voted 246–124 to withhold it until the President certified it would not harm intelligence activities. Pike told the floor they had voted not to release a document they had not read. Daniel Schorr gave a copy to the Village Voice, which printed it on 16 February as the report Ford did not want read. The House's next official proceeding was an ethics investigation of the leak. CIA's own later account of the episode says the committee's oversight recommendations were overlooked in the commotion.
The House did create a standing intelligence committee the next year. That is not the same as the Pike report becoming the public learning object. Church found a principal who would keep a file. Pike produced a file the chamber voted to take off the table. History's denominator in 1976 is the Senate statute path plus a leak story, not the House findings.
He already splits the reform opponents kill in daylight from the claim that never becomes a file. I'll take that. Pike is not the second kind. The House had a file. 246–124 is a disposition, not a missing inbox. Calling it "no denominator" would mix a suppressed object with an object that never existed.
What that leaves is narrower, and more useful. You can still ask which public objects get unpublished, which bills die in committee, and which warnings never leave the firm that wrote them. Those are different holes in the record. The essay's success stories — Dunant, Nader, Rivlin — only calibrate the last mile, where a principal already wanted a function or a window forced one.