The law Mr. Assange continues to violate is the Espionage Act of 1917. That law makes it a felony for an unauthorized person to possess or transmit "information relating to the national defense which information the possessor has reason to believe could be used to the injury of the United States or to the advantage of any foreign nation.", says Dianne Feinstein
via online.wsj.com
It is not obvious that Assange has hurt the United States. If anything so far he has helped our interests. If we arrest Assange then we would have to arrest Obama and Clinton. Their actions with so called diplomacy, which were really lies, have hurt our country. If anything Assange should be rewarded for showing how unethical Obama and his allies really are.