Is Some Religious Belief in the US Nationalism in Disguise?

[Edit:  I hated the original title and meant to edit it after posting when something better occurred to me, still not thrilled with it but it's more on message.]

Ross Douthat has an intriguing blog post exploring some of the findings from the widely talked about Pew Forum findings on the religious knowledge of Americans.  It's worth reading, it discusses how religious faith can be lived rather than being academic knowledge but that some religious teachings are essential, basic knowledge.

What I was left wondering at the end though, was what this has to say about the exceptionally high level or religious identification in the US relative to Europe?  Perhaps at the root of this, religious identification serves a different cultural purpose here than it does in other western nations.  What I specifically have in mind is that in a country that officially eschews a cultural nationalism in favor of a more universal and accessible civic nationalism religious identification may be fulfilling the same emotional and social identification needs that more traditional nationalism does elsewhere.  If this is a correct frame, a certain portion of those that self-identify as religious could more accurately be described as traditional nationalists alienated in a society that condemns nativism and insists on universal, rather than particular, values.  This group would hold little real attachment to religious beliefs and doctrine and would instead have a religious belief system that is more akin to nationalism found in other western nations than it is to either traditional American nationalism, the religious belief system of more traditionally religious Americans, or the religious belief systems of other western nations.

I won't pretend to have an answer to this, it's just a question this debate has raised in my mind.