>> I think there is an argument that Snowden's actions could have put at risk the former for the sake of the latter
This is actually addressed in the article:
"CIA, NSA and DIA (Defence Intelligence Agency) Directors all have been brought on the floor of the congress and they have been asked by my strongest critics, begged for any evidence, that any national security interest has been harmed, that any individual has come to harm. And not in any single case have they shown concrete evidence that this occurred."
This is actually addressed in the article:
"CIA, NSA and DIA (Defence Intelligence Agency) Directors all have been brought on the floor of the congress and they have been asked by my strongest critics, begged for any evidence, that any national security interest has been harmed, that any individual has come to harm. And not in any single case have they shown concrete evidence that this occurred."