Leaks from Edward Snowden triggered a much needed debate about surveillance in America, even if they jeopardised national security, the country's spy chief admitted.
National Intelligence Director James Clapper said: "As loath as I am to give any credit for what's happened, which is egregious, I think it's clear that some of the conversations that this has generated, some of the debate ... probably needed to happen."
Speaking at a conference in Washington, Clapper said the public debate about the best way to balance spying powers and privacy rights should "perhaps" have taken place earlier.
"So if there's a good side to this, maybe that's it," he said.
His comments on Thursday marked the first time a senior US intelligence official has acknowledged the leaks might not have had a solely negative impact.
Officials have previously labelled former National Security Agency contractor Snowden a traitor who endangered US interests and spies in the field.
Clapper, who oversees all 16 US intelligence agencies, predicted there would be more revelations from Snowden, and said he was worried about their long-term effects.
He said he was concerned about "the impact, frankly, on our national security and the damage caused by this continuous stream of revelations".
But he said the intelligence community should be more open about its work, even if that meant taking more risks, to ensure that Americans and their representatives in Congress trusted their spy services.
He said his office had this week declassified hundreds of pages of documents from the court that oversees electronic surveillance as part of an attempt to be more transparent.
"Transparency is a double-edged sword. It's great for us, great for our citizens. But the adversary goes to school on that transparency too," he said.
"But I'm convinced we have to err on the side of more transparency because, most importantly, we won't have any of this if we don't have the trust and confidence of citizens and their elected representatives."
Clapper said he met executives from some news media companies to discuss the fallout from the Snowden leaks and found a "big gulf" between how the two sides viewed what affects national security.
And he acknowledged that it was difficult to make the case publicly for current surveillance powers in the aftermath of a wave of bombshell revelations.
It was "a real challenge to sort of punch back and make the alternative case", he said.
"So one of the things we're doing is to try to open up, be more transparent, explain to people what we're doing."
Snowden, who has been charged with espionage by US authorities, has secured temporary asylum in Russia.
President Barack Obama has defended the National Security Agency 's surveillance as lawful, but has left the door open to more oversight from Congress or through other measures.