FIGHTING FOR AIR: In the Trenches With Television News by Liz Trotta (Simon & Schuster: $19.95; 377 pp.). “Vietnam spoiled him.” Television news veteran Liz Trotta cites that statement, from the lips of a co-worker, to try to explain the suicide of a fellow Vietnam correspondent years after the war ended. But the sentence is just as applicable to Trotta herself, for while she faithfully describes the major stories she covered over two decades as a network news reporter--and makes a point of settling many political and professional scores along the way--the book centers on her experiences in Southeast Asia. One of the first newswomen to break into TV, Trotta comes off here as a reporter of the old school: dogged, independent, more than a little righteous, and mad as hell that television news these days is more about style than substance. Trotta flourished in Vietnam (once she persuaded her NBC superiors to send her there), but didn’t do so well elsewhere, and “Fighting for Air,” between the lines, demonstrates why: She thrives on pressure, covering stories in an obsessive, no-stone-unturned way, and few events or employers let her exercise those all-consuming skills.