WHEN James Cole, the deputy attorney-general, explained to Congress in June how the National Security Agency (NSA) is held in check, he conceded, "Every now and then, there may be a mistake." Barack Obama insisted last week that it really was just every now and then. While discussing Edward Snowden's leaks, Mr Obama said that "what you’re not reading about is the government actually abusing these programmes and, you know, listening in on people’s phone calls or inappropriately reading people’s emails." Today you can read about the government actually abusing these programmes. The Washington Postreports that the NSA has overstepped its authority thousands of times each year since 2008, when Congress granted the agency broad new powers to conduct surveillance. The source of the report is Mr Snowden, who leaked an internal NSA audit and other top-secret documents to the paper.

The abuses don't appear to be systemic. "Most of the infractions involve unauthorized surveillance of Americans or foreign intelligence targets in the United States," says the Post. "They range from significant violations of law to typographical errors that resulted in unintended interception of U.S. e-mails and telephone calls." For example, when attempting to intercept communications abroad, a programming error mixed up the international dialing code for Egypt (20) with the area code of Washington, DC (202). As a result, a large number of calls from Washington were picked up.

Perhaps more troubling, the NSA didn't feel the need to report this and other violations to the agency's oversight staff. In other cases analysts showed a practised coyness in dealing with overseers. The checks on the agency, therefore, appear even weaker than presumed. Compounding the problem, the chief judge of the Foreign Intelligence Surveillance Court, which rules on matters of surveillance and counter-terrorism policy, tells the Post that the court is not equipped to independently verify whether the snoopers are telling the truth about their violations.

In some cases it doesn't matter, because the court is in the dark. A programme that sucked up domestic emails while trying to capture international data passing through American fibre-optic cables ran for months before the court declared it unconstitutional. Congress seems no better informed. The Post notes that Dianne Feinstein, chairman of the Senate Intelligence Committee, did not receive a copy of the leaked NSA audit until the paper asked her about it.

The audit, which details thousands of violations, counted only those in the NSA's Fort Meade headquarters (pictured) and other ­facilities around Washington, DC. Officials told the Post that the number of violations would have been "substantially higher" if it included other NSA facilities.

"We’re a human-run agency operating in a complex environment with a number of different regulatory regimes, so at times we find ourselves on the wrong side of the line,” whined an unnamed NSA official. Referring to the agency's violations in comparison to its total activity, he added, “You look at a number in absolute terms that looks big, and when you look at it in relative terms, it looks a little different.” But the NSA would rather you see nothing at all.

(Photo credit: AFP)