I'm fairly sure LTC Ralph Peters (retired) had all of his military time as a commissioned office in the military intelligence corps. He was a Major, MI, when he was assigned to Research and Analysis Directorate of the old US Army Intelligence and Threat Analysis Center in 1991. I had just moved from being the R&A Directorate Operations Officer to doing intel analysis in the Soviet/Warsaw Pact Division. Peters was suppose to be in the division, but was detailed to the Deputy Chief of Staff for Intelligence (DCSINT/G-2) as an analysis because of his reputation.
Regarding combat experience, he would have come into the Army at the end of the Vietnam war so missed it, but may have been in Operation Desert Storm. He retired to write books and be free to comment on military matters.
Peters enlisted in the Army as a private, and spent ten years in Germany working in military intelligence. Years later, during the 2004 Killian documents controversy, Peters pointed out that in his front-line division in 1977, five years after the memos in question were allegedly written, only the general's secretary had an electric typewriter. It was, he says, too primitive to produce the documents in question, and moreover, National Guard units "…got the junk we didn't want."
After returning from Germany, Peters attended Officer Candidate School and received his commission, eventually attending the Command and General Staff College and U.S. Army War College. His last assignment was to the Office of the Deputy Chief of Staff for Intelligence. He retired in 1998 with the rank of Lieutenant Colonel.
http://en.wikipedia.org/wiki/Ralph_Peters
Thank you.