Manning was a member of the military with access to classified data and she uploaded it to the internet for publication.

And, unlike Snowden, none of what she leaked revealed violations of the U.S. Constitution. Her judgement was terrible and she deserved to spend some time in prison for what she did.

Assange is a journalist, not a member of the military or even a U.S. citizen, and all he did was assist and enable the publishing of this classified data.

The cases are completely different.