Saul Bellow, who was Jewish but possessed no orthodox set of religious beliefs, didn't think so.
Or at least, this is his position in Ravelstein, the novel about Allan Bloom, but with the names changed.
He was responding to Ravelstein's (Bloom's) militant private atheism (although he was a public supporter of religion); Bloom made it clear that "no true philosopher could believe in God." Now, there are a few things to say about this. First, this is part of the "esoteric" teachings about which Straussians believe philosophers should not be up front. Although Bloom doesn't come right out and embrace this in The Closing of the American Mind, he pretty much admits, more toward the end of the book (if you read that far) that this is what he believes. Strauss, on the other hand, never as far as I know publicly admitted to being an atheist and even, as Robert Light informed me, made some public denials about it.
Strauss's textual teaching was that Reason and Revelation could not refute one another (that they sort of came to an impasse) and that material science could not disprove the existence of God. However, privately, I've heard from reputable second and third hand sources, he was as much of a militant atheist as Bloom. The Straussians, after Strauss himself, and revealed in Bellow's book, had no problem with "spilling the beans" to those in their inner circle. And Bloom was one of Strauss's closest philosophical confidants. So when we hear Allan Bloom say, "no true philosopher can believe in God," we are likewise hearing Leo Strauss say this. (Keep in mind, Bellow in Ravelstein names Leo Strauss, "Davarr" which is Hebrew for "Word.") I've also heard, again from secondary sources that Strauss could be heard saying things like "philosophers are paid not to believe in God."
Now, since Nietzsche, it does seem as if all prominent, post-Nietzschean philosophers are atheists. There is just something about the philosophic mindset where it goes with the territory. It's almost a dogma to them. What is interesting about the Straussians is that they believe that many pre-Nietzschean philosophers were secret atheists and that this was an esoteric Truth that one had to "read between the lines" to understand. So for instance, thinkers like Hobbes, Locke, Newton, Voltaire, all of whom professed to believe in some sort of God, were really atheists. I'm not sure if I can buy into this. What's true about all of these thinkers is that they either rejected the Christian God or if they claimed to believe in Him, they rejected traditional orthodox dogmas about God's attributes, like the Trinity. This is what Bloom meant when he wrote in Closing, "The philosophers appeared to deny the very existence of God, or at least of the Christian God."
Also, keep in mind, speaking one's true mind in those days could get one killed. Lest we be reminded that Calvin, as governor of Geneva had Servetus put to death for publicly denying the Trinity.
The Straussians argue that Nietzsche thought these Enlightenment philosophers, by putting reason and empiricism at the center of the political stage, had "killed God"...and that this was a catastrophe for man. But men, according to Nietzsche, need God. So new gods must be created by men (as all gods are).
In any event, Bellow seems to reject the notion that anyone really disbelieves in God and the afterlife. He writes,
[Bloom/Ravelstein] had, however, asked me what I imagined death would be like -- and when I said that the pictures would stop he reflected seriously on my answer, came to a full stop, and considered what I might mean by this. No one can give up on the pictures -- the pictures might, yes they might continue. I wonder if anyone believes that the grave is all there is. No one can give up on the pictures. The pictures must and will continue. If Ravelstein the atheist-materialist had implicitly told me that he would see me sooner or later, he meant that he did not accept the grave to be the end. Nobody can and nobody does accept this. We just talk tough.
Well, I guess they both now know.