Joanna asked about this a few days ago.
Go to the Stanford libraries and trawl through the J. of Military Socology (perhaps your local ublic library has access via your barcode to EBSCO and JSTOR databases for academic journals such as that?). Scholars like Lawrence Korb and Morris Janowitz have written a lot over their careers that addresses Joanna's question. Perhaps leftist anthropogist Catherine Lutz who has written a book on military cultures would have some material too.
(TOC and excerpt available, http://www.amazon.com/gp/reader/0262561425/ref=sib_dp_pop_toc/102-0685591-2389735?%5Fencoding=UTF8&p=S007#reader-link
I looked through this volume yesterday at the DPL has a wealth of survey data on the political leanings of the officer cor of the US military)
Soldiers and Civilians: The Civil-Military Gap and American National Security (BCSIA Studies in International Security) (Paperback) by Peter D. Feaver (Editor), Richard H. Kohn (Editor) "In a 1997 speech at Yale University, Secretary of Defense William Cohen raised the possibility of "a chasm . . . developing between the military..."