Will there be a religious war against Christan's and muslims aka WW3?

hey im a christian, and i was just wondering most of the U.S. is christian/Catholic etc. if we attack iran or somthing because we attack iraq afghan etc. could that lead too a WW3 aka a religious war?...ive also read things like we should drop a bomb on the whole middle east off the face of the earth(sorry but when i read that it was funny >_>)...what u think?...im leaving for the army basic in june. what do you think of the outcome?