There are some who believe that US national security was not harmed at all by the leaking of two classified surveillance program. There are even some who believe that the surveillance programs weren't tracking terrorists, but rather spying on Obama's enemies.

But somewhere between DNI Clapper's claim that the damage to our intelligence was "huge" and Glen Greenwald's contention that our intelligence "wasn't harmed at all" lies the truth of the matter, according to Politico:

Intelligence experts and former officials interviewed by POLITICO say there will likely be some harm to U.S. intelligence efforts -- though not in exactly the way many Americans might expect and not because the stories really revealed the crown jewels of American counter-terrorism efforts.

And the surest negative impact of the disclosures is more likely to fall on the U.S. Internet industry, as some of its international customer base flees in search of sites thought to be more secure from American government snooping.

Former officials say it's not so much the specifics of what was leaked as the huge wave of publicity the leaks generated: Every news story could serve as a revelation to some terrorists, and a reminder to others, of the nation's capabilities.

"It's kind of Darwinian," former National Security Agency Director Michael Hayden said. "The more stuff like this is in the public domain, we'll still catch terrorists, but it will be the stupid terrorists. ... The guys we should really be worried about will be far less likely to be swept up in this effort."

 

While many Americans view terrorists as careful and well-informed, ex-intelligence officials say that in reality, their skill sets run the gamut -- and the biggest terror threat in the United States right now actually seems to be homegrown extremists who are not hardened operatives and who lack first-rate tradecraft. These are the precisely the sorts of novices who could be tipped off or decide to behave more furtively precisely because of the recent spate of surveillance disclosures.

And, as Americans saw in April with the deadly attacks Tamerlan and Dzhokhar Tsarnaev allegedly carried out at the Boston Marathon, amateurs are still capable of inflicting serious damage.

"Intelligence agencies make a living off of other people's mistakes," said former NSA general counsel Joel Brenner. "You'd be surprised at how many people make mistakes."

It's no accident it took a decade to catch up with Osama Bin Laden. The al-Qaeda leader took extraordinary precautions against being detected. Most of his communications within the al-Qaeda network were by old fashioned messenger - trusted aides traveling thousands of miles sometimes to deliver instructions. He largely stayed off the grid and when he did use electronic communications, he apparently had state of the art encryption devices to mask his signature.

He moved frequently until around 2006 when he landed in Abbottabad. He had no phone service installed and had few other amenities that could be tracked by anyone looking for him.

Osama was one example of a terrorist practicing impeccable tradecraft. Most of the upper leadership of al-Qaeda is just as adept at becoming invisible. The point being, neither the phone suveillance program or the internet program would have detected any decently trained terrorist - unless they made a fatal mistake, which isn't unheard of.

So how much damage was done by the leaks? Even stupid terrorists can cause a lot of casualties. Alerting them to the existence of these programs will make them more cautious - but probably not invisible. I don't know how intelligence agencies assess damage, but making it harder to track an enemy has to be considered a minus.