The CIA could assasinate Julian Assange.
Terrific. Then what? It's not like Assange is carrying 300K documents on his person. Those are electronic files shared across a distributed network. There's no way to stop their dissemination. Once the documents were stolen off a "secure" server, they were as good as published.
The question isn't about how do you stop Assange, the question is how do you let a 20-year old E-3 have unfettered access to such material. That's what needs to be investigated.
Are you serious? Information once leaked cannot be controlled anymore. This is not the 80s you know? Assassinations are meaningless in preventing flow of information.