What is the main conflict in Dispatches by Michael Herr?

Michael Herr, a writer in his late twenties, takes a correspondent position with Esquire Magazine to report on the Vietnam War. He covers two major operations, the siege of Khe Sahn and the recapture of Hue, the old Vietnamese capital, plus several other field operations. He meets many Marines, several officers, and fellow correspondents while gathering the impressions and experiences contained in his dispatches.