The leaks from NSA whistleblower Edward Snowden about US worldwide surveillance have helped rather than harmed America, and the leaks haven't endangered lives.

Lawrence "Larry" Wilkerson, the former chief of staff to Secretary of State Colin Powell in the last Bush administration, said that he believed Snowden's assertions that he leaked out of concern for the US breaking both domestic and international law.

"I think Snowden has done a service. I wouldn't have had the courage, and maybe not even the intellectual capacity, to do it the way he did it," he told Salon magazine.

"There's a logic to what he has done that is impressive. He really has refrained from anything that was truly dangerous, with regard to our security – regardless of what people say."

Wilkerson, who played a key role in gathering intelligence to justify the 2003 invasion of Iraq, said that Snowden and the journalists working with him had been "circumspect" in what data they had released, and thinks the fugitive's decision to go public was driven by "altruistic" reasons.

"Snowden seems to me to be pure as a driven snow," he said. "You can be dangerous if you're that way, but you can also be helpful. And I think he's been more helpful than dangerous."

Despite his apparent admiration for Snowden, Wilkerson said that the former NSA worker had made his bed and now would have to lie in it.

"I credit Snowden for having a great deal of courage, because he's ruined himself forever," he said. "I don't think he has a future. He has a future so long as he can continue to co-exist with all the restraints and pressures around him. But I'm not sure that's being long-lived. And I don't see him ever being accepted back here." ®