In countries where the head of state is different from the head of government, is the former a potential target of prosecution by the International Criminal Court?
For example, if the ICC were to make prosecutions over the 2003 invasion of Iraq (unlikely, but as an example), would Elizabeth II, who is Queen of the United Kingdom, Queen of Australia, and possibly some other countries involved, be a potential target of prosecution?
As far as past prosecutions unrelated to the ICC are concerned, I'm aware of the example of WWII with regards to Japan. Hideki Tojo, head of government for much of WWII, was executed, while the Americans went out of their way not to prosecute the Emperor Hirohito (I suspect for reasons more related to politics than law).