But of course, a category like that is so broad as to be philosophically meaningless. As Luther says, "that upon which you set your heart and put your trust is properly your 'god.'" He is at pains to point out that not all the 'gods' intended by this definition are God. Luther points especially to money and possessions, but there are plenty of other false gods, worshiped devoutly by the masses: country, family, self-esteem, you name it. The Times Book Review, even.
Even those who happen to call their god by the name "God," or by any of the various historic names which are often denoted in English by that awkward catchall (YHWH, Allah, Father-Son-and-Spirit, among hundreds of others) do not mean the same thing. "God," to Christians, is incarnate and triune; this is, irreducibly, who God is. Without both characteristics, God is not God from the perspective of Christian theology. Yet to both Jews and Muslims, a god with these characteristics simply is not, and cannot be, God.
The true situation, however, is far more complex than this. Not only between religious traditions, but within any single tradition, there are competing images of God. Sometimes, the competition becomes so fierce that the majority labels the minority "heretical." (The Arian God is not the Orthodox God). More frequently, the differing parties agree to disagree. (The God present in, with and under the eucharistic elements is, at least arguably, not the God whose only true presence is localized in heaven.) But most often, the differences persist, unspoken and scarcely acknowledged, between those who are ostensibly united by a single faith. (Some of our own church members believe that God receives the blessed dead immediately and spiritually, others that God is waiting to revive everybody, physically and together).
This may sound like Scholastic nitpicking, but it is not. Because there are some people who believe that "God" requires them to kill for religious reasons -- think of jihadists and Crusaders. There are others who believe that "God" permits them to kill, under certain circumstances, such as war and self-defense -- the traditional position of Constantinian Christians, and virtually all Jews, Muslims, Hindus, Sikhs, and many more Buddhists than most Americans realize. And there are some who believe that "God" absolutely forbids them to kill -- most Anabaptist Christians, many Buddhists, all Jains. These people worship different and distinct gods.
Although it is customary to lump, say, Lutherans and Mennonites together under the label "Christian," the truth is that, from this perspective, they hold a dramatically different doctrine of God. Which is nothing more than a theological way of saying that they impute different attributes to the ultimate reality -- or that they believe in different gods. From the perspective of the public square, Mennonites and Jains worship the same deity, at least functionally. As do Bin Laden and Ann Coulter.
So when we hear that 92% of our compatriots believe in a god, we are not much moved to displays of triumphalism. A little phenomenology of religion and a smidge of pastoral experience combine to convince us that the respondents are not united by any nebulous thing called "faith," but rather divided by their many separate gods.
Which is why the American Constitution, while allowing all 92% to hold their beliefs unmolested, requires the government to function as though the remaining 8% were right.