NSA chief Alexander to testify on classified leaks in rare public hearing

National Security Agency chief Gen. Keith Alexander will address the House intelligence committee on Tuesday in a rare public hearing that could shed new light on the scope of the federal government’s classified phone and Internet surveillance programs.

The session involving two of Washington’s most secretive bodies comes as an NSA leaker,  former contractor Edward Snowden, threatens to reveal more government secrets from his hiding spot in Hong Kong.

Alexander has already gone to Capitol Hill several times since Snowden revealed details earlier this month about the government programs -- to discuss the agency’s budget and meet privately with congressional members.

But the upcoming meeting, titled “How Disclosed NSA Programs Protect Americans, and Why,” will be the first time Alexander speaks publicly about the agency-led surveillance programs.

The meeting will also come one day after Snowden, the former NSA contractor who gave the classified documents to journalists, conducted an online chat for The Guardian in which the self-proclaimed whistleblower wrote: “Truth is coming and it cannot be stopped.”

Officials say the meeting is part of the House Permanent Select Committee on Intelligence’s continuing oversight of the agency.

But they also acknowledge it will be “an opportunity to discuss how the disclosed NSA programs protect Americans from terror attacks on U.S. soil and why the disclosure of that classified information aids our adversaries.”

Among the most pressing questions now are which programs and how many of them either log phone or email records or allow analysts to eavesdrop on conversations or read electronic messages.

Other concerns include under which circumstances are warrants needed from the FISA court, which rules apply to domestic or overseas surveillance and if such efforts, legal under the post-9/11 Patriot Act, expanded under the Obama administration.

Attorney General Eric Holder said Friday the leaks were "extremely damaging" and vowed that the person responsible would be held accountable.

However, he did not mention Snowden by name nor say formal charges have been filed, saying only the case is under investigation.

Members of Congress have defended the programs, saying they helped thwart numerous terror plots including a 2009 attempt to blow up New York City subways. The claim was substantiated Saturday when U.S. intelligence officials declassified information on the plot and said the programs have foiled as many as 20 domestic and foreign plots.

On Sunday, former Republican Vice President Dick Cheney called Snowden “a traitor” but said Alexander is a “superb guy” and defended the programs.

“The reason we got into it was because we've been attacked,” he told Fox. “There's going to be another attack, and they'll have deadlier weapons than ever before.”

Also scheduled to testify Tuesday are Deputy Attorney General James Cole, Deputy FBI Director Sean Joyce, and Robert Litt, general counsel for the Office of the Director of National Intelligence.