It can be tough to imagine what exactly was going through the minds of National Security Agency officials when they decided they could secretly collect American citizens' private data in bulk. On stage at Yahoo's Digital Democracy conference in Des Moines, Iowa this week, the NSA's former general counsel, Matt Olsen, attempted to explain.

A common misconception, Olsen says, is that the NSA began collecting the data without giving any thought to how controversial the program would be if word got out. "For all the time I worked on all of these issues, this was a constant discussion," Olsen says. "How do we calibrate what we’re trying to do for the country with how to protect civil liberties and privacy?"

Unfortunately, judging by the outrage Edward Snowden's revelations inspired across the country—including among government officials like Senator Rand Paul, who spoke at the conference earlier that day—it seems the NSA didn't calibrate quite correctly. Gregory T. Nojeim, a senior counsel at the Center for Democracy and Technology who joined Olsen on stage said as much. "I don't doubt that there were discussions," he said, "I just think they came out the wrong way, and the reason things are coming out the wrong way is because of excess secrecy."

But the program would never have worked without a high degree of secrecy, Olsen said. For proof, he pointed to the fact that after Snowden uncovered the NSA's activity, the NSA "lost coverage of terrorists."

"We saw people we were targeting with NSA surveillance stop using communication at all," he says. "We saw them go to different service providers. We saw them go to uses of encryption, different ways in which they were reacting to what they were seeing."

The biggest problem, Olsen says, was not only that Snowden's revelations exposed the data collection, but that it also exposed so many other details about how and where the NSA operates. "How it conducts surveillance, who it work with, where it is overseas, exactly how it’s able to target terrorists, all of which—the vast majority of which—have nothing to do with US citizens' privacy and civil liberties," Olsen said. "It shouldn't be a surprise that it’s made the job harder for the intelligence community."