Chelsea Manning wasn't the only soldier to receive a pardon after leaking military endeavors.
The United States and Israel developed the Stuxnet virus, which infected computers in the Iranian nuclear program to cause malfunctions in their centrifuges. But the secret program was exposed by Newsweek and New York Times reporters, and the trail led back to a four-star general, the former vice chair of the Joint Chiefs of Staff. Cartwright actually fainted when he realized that investigators were on to him.
There has always been something strange about the case, as it's clear that Cartwright wasn't the sole source of the leaks. Obama's pardon could come as apology for making Cartwright the victim of infighting over whether America's cyberwar capabilities need to be public to serve as an effective deterrent – a position Cartwright vocally held.