Is Spying on Terrorists a Crime?

I saw Professor Johnathan Turley from my alma mater, GW Law School, on TV last night talking about the NSA spying program. He stated his view that the program was a federal crime and was much more serious than a technicality such as neglecting to give Miranda warnings. Indeed, the FISA act does provide for criminal penalities when an American is put under surveillance without authorization. I hadn't know this before reading about the FISA act on the web recently. There does seem to be a case that Bush committed a serious crime. Some scholars accept the idea that the authorization of the use of force gave Bush the power to authorize the surveillance since keeping an eye on your enemies is traditionally part of military operations. Others reject this notion as too much of a stretch. Charles Krauthammer in his column describes the program as a political mistake, not an impeachable crime and says, "This tug of war is a bipartisan and constant feature of the American system of separation of powers." Other presidents ignored congressional mandates such as Reagan giving support to the Contras despite the Boland Amendment. I have to say that if you accept the notion we are at war it's a little hard to take the impeachment talk seriously. Would anyone have balked at FDR authorizing surveillance of conversations between Americans and known Nazi agents during World War II. Despite the lack of an official declaration, can anyone doubt we are at war with Al Quaida?