The NSA has been on the defensive ever since Edward Snowden revealed its massive spying programs in a series of leaks earlier this month. The agency has been called into Congress for multiple hearings to defend the programs and to reassure Americans that they’re not being spied on. Even after multiple assurances, some senators still aren’t buying it.

Sens. Ron Wyden and Mark Udall have sent a letter to NSA Director Keith Alexander asking him to come clean. In particular, they point out that the NSA has sent conflicting messages to Congress over the years and they want to know the real story once and for all.

The letter opens by referencing a fact sheet that the NSA sent to Congress that “contains information about both section 702 of the Foreign Intelligence Surveillance Act (FISA) and section 215 of the USA Patriot Act.” These two laws are what permits the NSA to collect phone and Internet records.

The senators point out that the fact sheet contains a glaring inaccuracy:

“We were disappointed to see that this fact sheet contains an inaccurate statement about how the section 702 authority has been interpreted by the US government. In our judgment, this inaccuracy is significant, as it portrays protections for Americans’ privacy as being significantly stronger than they actually are. …

We urge you to correct this statement as soon as possible. As you have seen, when the NSA makes inaccurate statements about government surveillance and fails to correct the public record, it can decrease public confidence in the NSA’s openness and its commitment to protecting Americans’ constitutional rights. Rebuilding this confidence will require a willingness to correct misstatements and a willingness to make reforms where appropriate.

Separately, we note that this same fact sheet states that under 702, “Any inadvertently acquired communication of or concerning a US person must be promptly destroyed if it is neither relevant to the authorized purpose nor evidence of a crime.” We believe that this is somewhat misleading, in that it implies the NSA has the ability to determine how may American communications it has collected under section 702, or that the law does not allow the NSA to deliberately search for the records of particular Americans. In fact, the intelligence community has told us repeatedly that it is “not reasonably possible to identify the number of people located in the United States whose communications may have been reviewed under the authority” of the FISA Amendments Act.”

The last paragraph is the real kicker as Wyden and Udall have essentially caught the NSA with its pants down. As TechDirt points out, the agency told Wyden two years ago that it couldn’t see how many Americans were accidentally spied upon, but its latest statement says that it totally can.

With this potential embarrassment, the senators are hoping the NSA and the Obama administration will finally welcome the public debate that was promised earlier this month:

“We believe that the US government should have broad authorities to investigate terrorism and espionage, and that it is possible to aggressively pursue terrorists without compromising the constitutional rights of ordinary Americans. Achieving this goal depends not just on secret courts and secret congressional hearings, but on informed public debate as well.”

There’s no time listed by which Gen. Alexander must respond, but the NSA is usually pretty good about responding to Congress in a timely manner. Just don’t expect a complete answer.

[h/t: TechDirt]