What is the correct way to write "God bless America"?
I've seen people write "God bless America", and it drives me nuts.
Shouldn't it be "God, bless America"?
Grammatically, I like to think of it as "May God bless America." The mood of the verb is subjunctive. The "may" is just dropped for conciseness.
You'll notice you also say things like, "I'd rather that he leave early..." (not "leaves"). You are using the subjunctive mood, which isn't grammatically overt in English all that often, but does pop up here and there. "God bless America" is one of these cases.
http://en.wikipedia.org/wiki/English_subjunctive#Usage