Can one believe in God but not religion?
My answer would be yes.
But then being half Jewish / half Catholic, I suppose the only way I can reconcile the two is by believing it's the same God, with the same basic tenets, we simply choose to express our beliefs in different ways. I was perfectly happy to go to church on Sunday with friends on the basis that I agree with much of it; just as I am happy to go to synagogue although I disagree with the requirement to uncriticaly support everything Israel does.
Although fervent Christianity has become a requisite in American politics today, in the past it was less of an issue. Several of the Founding Fathers, although nominally Christian, are better described as Deists - at least one rejected the whole story of Jesus, and since acceptance of Christ is the key tenet of Christianity ...
It's also worth remembering that America was founded, populated and built by valiant men and women fleeing persecution in the Old World. We tend to focus of the Pilgrims who came over on the Mayflower, but there are other examples. French Protestants fled to Florida in the 1500s; unfortunately they were persecuted and massacred by the Catholic Spanish.
In some ways Christianity itself sprung up as a protest first against the organised Jewish state religion of Israel, and then against the organised pagan state religion of Rome.
"@AJEnglish: Can you believe in God and not organized religion? The question Anne Rice says 'quitting' #Christianity raised http://aje.me/pbYUvf"
So the short answer to the question is "yes" - but history shows us that God abhors a vacuum, so a new sect will soon spring up to fill the void.