If U.S. prosecutors ever get their hands on Edward Snowden, they’ll play such a tympanic symphony on his skull he’ll wish his hands never touched a computer keyboard. Should U.S. prosecutors fail, U.S. diplomats will squeeze — as they did in Hong Kong — until he squirts from his hiding place and scurries away in search of a new sanctuary. But even if he finds asylum in a friendly nation, his reservation will last only as long as a sympathetic regime is calling the shots. Whether he ends up in Venezuela or some other country that enjoys needling the United States, he’ll forever be one election or one coup away from extradition.

Even then, he won’t be completely safe.

“Always check six, as we said when I used to be a flyer in the Air Force,” said NSA whistle-blower Thomas Drake recently. “Always make sure you know what’s behind you.”

Solitary whistle-blowers like Snowden, Drake and Daniel Ellsberg draw targets on their backs with their disclosures of official secrets, either by leaving a trail from the heist scene, being the most logical suspect, or because they admit their deed. Escaping prison time, such whistle-blowers have learned, depends on the luck of prosecutorial overreach (Drake) or self-destruction by the state, which derailed the prosecution of Pentagon Papers liberator Ellsberg.

The solitary whistle-blower, usually a career government employee, isn’t really a leaker, as Stephen Hess explains in his enduring typology of leakers. Typically, the whistle-blower seeks revolutionary change, not piecemeal reform. He doesn’t share information with journalists to purchase their goodwill or to loft a trial balloon or to give himself an ego boost. He’s motivated by principle, not self-interest or Machiavellian intrigue, and seeks to correct what he considers an intolerable wrong. And in most cases, his whistle-blowing results in career suicide if not jail time.

Most leakers — mindful of the fate of the pure and solitary whistle-blowers — scale the size of their leaks to avoid detection. Rather than giving the whole puzzle away to reporters, they break off pieces for distribution, in hopes that it can’t be traced back to them. Or, if crafty, leakers dispense pieces of the puzzle that aren’t especially revealing and therefore not precisely classified, but provide hints about the location of the next puzzle piece. Investigative reporters who excel at fitting a mosaic together benefit the most from this class of leaker.