Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
What's the U.S. plan on Russia's "all out" invasion? Plus, a look at the strategy for fighting ISIS.
Revelations that the National Security Agency has engaged in widespread surveillance on American citizens have galvanized many in Washington.
The White House on Monday defended the administration's stance on the initiatives, calling them a necessary middle way between total privacy and unacceptable threat.
But Edward Snowden, the former intelligence worker who outed himself as the man responsible for leaking details of U.S. surveillance programs, told The Guardian newspaper such programs are excessively intrusive.
Director of National Intelligence James Clapper told NBC on Saturday that the NSA leaks are "literally gut-wrenching ... because of the huge, grave damage it does to our intelligence capabilities."
The Guardian's Glenn Greenwald, who first broke the story of the NSA's broad surveillance, disagrees.
"Terrorists already know that the U.S. government tries to surveil their communications. Nothing that we revealed helps, quote, unquote, "the terrorists." All we did was tell our fellow citizens in the United States and around the world the extent and capabilities of how vast this surveillance state is and the reasons why it needs scrutiny and accountability," Greenwald told CNN.
"The only things we've damaged are the reputation of American political officials and not national security," he said.
Greenwald sent a tweet Sunday, telling Clapper to "save some melodrama and rhetoric for coming stories, you'll need it."
"We do have more big stories coming, without question," said Greenwald.
And "when the U.S. government says what they say in every single case, when you uncover their secret misconduct, which is, 'These people have endangered national security and ... people should be afraid that they're going to be attacked by the terrorists,' we should all be rational and not simply accept that claim."
"I defy anybody ... to go and look at what it is that we published over the last week and describe how any of that could have harmed national security," said Greenwald.
Watch our full interview with The Guardian's Glenn Greenwald in the video below, or by clicking here.