It was one of the strangest personal crusades on Capitol Hill: For years, Sen. Ron Wyden said he was worried that intelligence agencies were violating Americans' privacy.

But he couldn't say how. That was a secret.

Wyden's outrage, he said, stemmed from top-secret information he had learned as a member of the Senate intelligence committee. But Wyden, a Democrat, was bound by secrecy rules, unable to reveal what he knew.