I've often heard and read about the idea of a collective national philosophy, but personally thought that any group as large as a nation would be far too diverse to generally agree about anything.
It seems to me that any ideological trends one might attribute to a nation would really mostly be present within the more influential members of the society in question.
More accurately, I find Gilbert Murray's idea of a self-evident core philosophy, refined by specific interests, much more appealing than, say, the notion of all Americans striving for universal liberty - to whichever extend they would even be able to agree on a definition of the term.
This idea is, unsurpisingly, called nationalism and has a huge bibliography. Follow the wiki page and start clicking through the "see also" sections at the bottom of the pages.
Giants of the field include Benedict Anderson, Eric Hobsbawm, Anthony D. Smith, Ernest Gellner, Elie Bedourie, and Hans Kohn -- this is not comprehensive by any means.
Some basic lists on Nationalism:
Hope this helps a little. Happy reading!