All of the comments taking umbrage that the article isn't celebrating Snowden's character are missing the point. While it is entirely possible that he was qualified or even overqualified for the position he had at Booz Allen Hamilton, nothing in his resume suggests that which raises the question who else has access to sensitive data and secrets? The answer could be that Snowden was an exceptional individual and that'…
The security clearance process basically looks for reasonable, honest Americans free of foreign influence. If government actors are abusing their power to such an extent that reasonable, honest Americans free of foreign influence feel morally obligated to blow the whistle, then there are going to be more leaks. It's not a flaw in the system; It's a safeguard against corruption and abuse of the system.
That might be enough for domestic intelligence, but it's really shooting yourself in the foot if you apply "free of foreign influence" to overseas intelligence operatives. (Because you'll never be able to recruit anyone whose exposure to the target culture is significantly deeper than a semester attending a foreign university ...)