National Security Agency Director Gen. Keith Alexander speaking at the American Enterprise Institute. (Chip Somodevilla/Getty Images)

The National Security Agency recently asked Verizon to turn over telephone metadata for tens of millions of Americans, the Guardian reported Wednesday, based on a leaked court document that appears to show an NSA request for customer data from April through July.

The NSA is both vast and secretive, one of the less-understood agencies of the U.S. intelligence community. And at the top of it is Gen. Keith Alexander, the longest-serving NSA chief ever, who took over in 2005 and is planning to retire early next year. His tenure, like so much the NSA has done in the past decade, has been controversial from the beginning. At the end of the year he took over, it was revealed that the Bush administration had authorized the NSA to run a vast, warrantless program spying on Americans.

Alexander has tried to balance these domestic NSA spying programs and his efforts to improve the agency's image, not always successfully. Sometimes those two goals can clash in a very visible way. Just two weeks ago, at a Reuters "cybersecurity summit" event in Washington, D.C., Alexander argued that the NSA was too busy protecting Americans to spy on them. Reuters, in a recent profile of Alexander, reported this surprising quote from the summit:

According to Alexander, the NSA has its hands full keeping tabs on potential terrorists, and does not have the bandwidth to read the 420 billion emails generated by Americans each day — even though some foreign governments were trying to do that.

"The great irony is we're the only ones not spying on the American people," he quipped.

Reuters added that Alexander " has tried to make the NSA appear more transparent, criss-crossing the country to talk about cyber issues. He likes to pepper his speeches with jokes, once blaming his late arrival at a Washington event on a 'distributed denial of service' hacking attack on city street lights."

Talk about awkward timing.