In response to claims by Edward Snowden that he raised concerns about NSA spying in emails sent to the spy agency's legal office, the NSA released a statement and a copy of the only email it says it found from Snowden.

That email, the agency says, asked a question about legal authority and hierarchy but did not raise any concerns.

"NSA has now explained that they have found one e-mail inquiry by Edward Snowden to the Office of General Counsel asking for an explanation of some material that was in a training course he had just completed," the NSA said in a statement. "The e-mail did not raise allegations or concerns about wrongdoing or abuse, but posed a legal question that the Office of General Counsel addressed. There was not additional follow-up noted.

"There are numerous avenues that Mr. Snowden could have used to raise other concerns or whistleblower allegations," the statement continued. "We have searched for additional indications of outreach from him in those areas and to date have not discovered any engagements related to his claims."

But Ben Wizner, Snowden’s legal advisor and director of the ACLU's Speech, Privacy, and Technology Project, said the NSA is being disingenuous.

“Snowden raised many complaints over many channels," he said in a statement today. "The NSA is releasing a single part of a single exchange after previously claiming that no evidence existed.”

The email, dated April 5, 2013, which was sent shortly before Snowden departed Hawaii for Hong Kong and released thousands of NSA documents to journalists, asks a question about the agency's mandatory USSID 18 training and Executive Orders – orders that come from the president.

In his email, Snowden asked about the hierarchy for such presidential orders, asking whether these have the same precedence as law.

"My understanding is that EOs may be superseded by federal statute, but EOs may not override statute. Am I correct in this?" he wrote. He also wanted to know which of Department of Defense regulations and regulations from the Office of the Director of National Intelligence have greater precedence.

There is no mention of a concern about how the NSA is using these regulations or overstepping its legal bounds. This does not, however, rule out that other emails from Snowden exist that the NSA has not found or is not releasing.

Snowden said in an interview with NBC Nightly News, aired last night, that he registered his concerns about the government's surveillance via official and unofficial NSA channels on a number of occasions.

“The NSA has records, they have copies of emails right now to their Office of General Counsel, to their oversight and compliance folks, from me raising concerns about the NSA’s interpretations of its legal authorities,” he said.

“I reported that there were real problems with the way the NSA was interpreting its legal authorities, and the response more or less in bureaucratic language was, ‘You should stop asking questions,’” he said. “These are recent records; this isn’t ancient history. One of my final official acts in government was continuing one of these communications with a legal office.”

Snowden told the Washington Post previously that he had raised concerns with the NSA more than 10 times before he resorted to leaking documents to journalists.

He also says he raised his concerns with supervisors and colleagues, many of whom were shocked by the programs and agreed with him that the NSA might be going too far but warned him that he would be destroyed if he made an issue of it.*

The NSA continues to insist, however, that Snowden did not raise concerns.

In the one email the NSA did release, Snowden's question about Executive Orders is a relevant and important one, however, even if he did not directly register his concerns. This is because the NSA used Executive Order 12333 to collect foreign intelligence abroad in a manner that doesn't require it to seek permission from the Foreign Intelligence Surveillance Court.

The NSA has called EO 12333 a "foundational authority by which NSA collects, retains, analyzes and disseminates foreign signals’ intelligence information" that primarily targets “communications by foreign persons that occur wholly outside the United States.” Such collection, however, is a concern because it can also vacuum up the communication of U.S. citizens, whether inadvertently or not, without oversight from the FISA Court.

In its response to Snowden's April inquiry, the NSA's Office of General Counsel wrote that Executive Orders "have the force and effect of law" but that they do not override statute.

With regard to the reference in Snowden's email to his USSID 18 training, this refers to United States Signals Intelligence Directive 18 — an NSA rule that bars overseas surveillance of Americans without authorization and probable cause.

Generally, when incidental interception of American communications occurs, there are procedures for handling these intercepts. Under USSID 18, recordings of such calls are supposed to be abandoned and destroyed when a U.S. citizen is identified. The only exceptions to this rule are when the attorney general affirms that the surveillance target is believed to be an agent of a foreign power, or the purpose of the collection is to acquire "significant foreign intelligence information."

William Weaver, who worked in the U.S. Army signals intelligence for eight years in Berlin and Augsberg, Germany, told Wired in 2010 that USSID 18 training was taken very serious.

"The way USSID 18 was treated by us was that it came down from God and was sacrosanct," said Weaver, now an assistant professor of political science at the University of Texas, El Paso. "We were told at training and many times after that, that if you violated USSID 18 you could spend the rest of your life in prison. The mindset was that you do not intercept U.S. citizens. And the minute you recognized that you intercepted, you immediately reported up the chain of command."

Some of Snowden's revelations over the last year, however, have indicated that the government is not careful about the collection and handling of U.S. communications.

The ACLU's Wizner says the issue around the email the NSA released is "a red herring."

"The problem was not some unknown and isolated instance of misconduct," he said in his statement. "The problem was that an entire system of mass surveillance had been deployed – and deemed legal – without the knowledge or consent of the public."

* UPDATE 5.30.14: Snowden, in an exchange with the Washington Post, called the NSA's release of a single email "tailored and incomplete." He said that the release "does not include my correspondence with the Signals Intelligence Directorate’s Office of Compliance, which believed that a classified executive order could take precedence over an act of Congress, contradicting what was just published.

"It also did not include concerns about how indefensible collection activities - such as breaking into the back-haul communications of major US internet companies - are sometimes concealed under E.O. 12333 to avoid Congressional reporting requirements and regulations."

He added that '[u]ltimately, whether my disclosures were justified does not depend on whether I raised these concerns previously. That’s because the system is designed to ensure that even the most valid concerns are suppressed and ignored, not acted upon. The fact that two powerful Democratic Senators - Ron Wyden and Mark Udall - knew of mass surveillance that they believed was abusive and felt constrained to do anything about it underscores how futile such internal action is – and will remain – until these processes are reformed."