This week, the chief judge of the Foreign Intelligence Surveillance Court (FISC) defended his court as an adequate bureaucratic check on government surveillance, denying that the court is merely a "rubber stamp," as critics have argued.

The court, after all, famously approves nearly all of the government’s final applications for surveillance (PDF).

"It is a kangaroo court with a rubber stamp," Russell Tice, a former National Security Agency analyst-turned-whistleblower, told The Guardian in early June 2013.

But as FISC Judge Reggie Walton noted in July of this year, that view doesn’t take into account the collaboration between the FISC and the government to make surveillance applications more palatable.

In a newly published letter (PDF) to top members of the Senate Judiciary Committee dated October 11, 2013, Judge Walton writes:

During the three month period from July 1, 2013 through September 30, 2013 we have observed that 24.4% of matters submitted ultimately involved substantial changes to the information provided by the government or to the authorities granted as a result of Court inquiry or action. This does not include, for example, mere typographical corrections. Although we have every reason to believe that this three month period is typical in terms of the historic rate of modifications, we will continue to collect these statistics for an additional period of time and we will inform you if those data suggest that the recent three months were anomalous. It should be noted, however, that these statistics are an attempt to measure the results of what are, typically, informal communications between the branches. Therefore, the determination of exactly when a modification is "substantial" and whether it was caused solely by the FISC's intervention, can be a judgment call.

“The process remains opaque”

Not surprisingly, civil libertarians aren’t very comforted by this view.

“The statistics shouldn’t reassure anyone who’s worried about the scope of the government’s surveillance activities,” Jameel Jaffer, an ACLU deputy legal director, told Ars. “The [FISC] can’t unilaterally amend the surveillance laws, and those laws give the government extremely broad authority to monitor Americans’ communications. And documents made public over the last few months show that the FISA court has generally interpreted those laws in the broadest possible way.”

Other legal experts suggest that this new letter raises even more questions than it answers.

“Even after Judge Walton's letter of October 11, the process remains opaque,” Ruthann Robson, a law professor at the City University of New York, told Ars.

“As described in Judge Walton's letter, it also places the Court in the position of assisting and advising the Government. What would be more transparent would be the total number of applications submitted and the number granted. Within that number, it would also be interesting to know how many were modified after the Court's suggestion—and whether that modification narrowed or possibly expanded the information being requested.”

Fred Cate, a law professor and the director of the Center for Applied Cybersecurity Research and Institute for Information Policy Research at Indiana University, also told Ars that the letter "misses the major objections to the way the FISC works today, for example, in secret, without opposition, and dependent entirely on the agencies appearing before it for information on the surveillance, the technologies, the protections in place, and the likely impact."

One former senator who helped pave the way for the creation of the Foreign Intelligence Surveillance Act (FISA) and the FISC, has previously told Ars that the court isn’t acting how he would like it to be.

“I think one has to be disturbed to learn as we recently have that more than 1,800 applications and [around] more than 1,800 approvals have been made by the court," Gary Hart, a former Colorado senator who sat on the Church Committee, told Ars in June 2013.

“I would be a little more comfortable if there were more rejections,” he said.