Indiscriminately leaking thousands of diplomatic cables is the kind of thing that can change the world forever. It can cause major treaties to fall through, wars to start, etc.
Just as an example, Manning's leaks have been cited as a major contributor to the Arab Spring that has left thousands of people dead, thrown Europe into turmoil, and is in the process of potentially ending the EU due to backlash against migration.
In honesty, the punishment should be death, but given that Manning was a deeply troubled young man, 35 years with the possibility of parole in 10 years is fine with me.
So what is the logic of 35 years? The way you describe it, it should be a life sentence. What is the purpose of prison in this case? And why not 15 years, or 50?
The purpose of prison is to strike fear deep into the hearts of those who would follow in Private Manning's footsteps. And actually, the sentence was 35 years with eligibility for parole in 8 years. There is always a certain arbitrariness to choosing sentences.
