TL;DR: no, not really.

While I too enjoyed Sorley's book, you must remember that his is only one argument out of many. Sorley is one of the more well known Vietnam War revisionists. In this case, "revisionism" refers to a body of scholarship that generally holds that the US could have won the Vietnam War had it not been for a variety of factors such as the antiwar movement and incompetent leadership. This argument stands in direct conflict with orthodox Vietnam scholars, who generally argue that the US could not have won the war absent strategies that every Vietnam-era president deemed unacceptable, such as sending one million troops or using nuclear weapons. Full disclosure: I am an orthodox scholar. Indeed, revisionists constitute a minority, albeit a significant one, of Vietnam War scholars.

Sorley's specific argument regarding how the war could have been won bears repeating. His 1999 book A Better War dealt with Creighton W. Abrams, who replaced Westmoreland as COMUSMACV (Commander, US Military Assistance Command, Vietnam) after the Tet Offensive. In this book Sorley argued that Abrams masterminded a brilliant strategy that focused heavily on counterinsurgency and pacification rather than attrition. This shift, according to Sorley, meant that the US experienced massive successes in Vietnam during the Nixon years, to the point where by 1972, most of South Vietnam was pacified, the NLF (National Liberation Front, or Viet Cong) was no longer an effective fighting force and North Vietnam was on the ropes. Sorley argues that despite this military victory, the US still lost in Vietnam because Westmoreland's ill-conceived strategies led to the US being mired in a frustrating stalemate for too long, which in turn caused the American public and Congress to sour on the war and pull out US troops and funding before the job was done. This argument, which is now known as the "Better War thesis" is interesting, but is also somewhat controversial, because Sorley does not account for a number of important factors, namely that American strategy and tactics in Vietnam during the Nixon years did not change that much in practice despite Abrams' focus on pacification. For example, he cites the large number of peasants who moved close to American bases during the late 1960s and early 1970s as proof that American pacification operations were bearing fruit, without considering that these civilians may have been trying to escape US bombing raids.

I bring up Sorley's past work because it's important to understand his overall argument when we try to evaluate his bio of Westmoreland. According to Sorley, Westmoreland is the principal reason why the US lost in Vietnam, and he bears the blame for the attrition strategy. The problem with this line of thinking is that other scholars have argued rather convincingly that Westmoreland was a symptom, not a cause. The Army of the Vietnam era suffered from profound institutional rot, and this particular fish rotted from the head down.

In the 1960s, the US Army was at something of a crossroads. After contributing to the successful effort against Hitler and Tojo, it had fought an extremely frustrating war in Korea. And because of nuclear weapons and the advent of strategic bombing, there were serious doubts among many military planners about just how necessary infantry would be in future wars. That sense of the Army being of secondary importance, when combined with how unpopular Korea had been, meant that many senior Army officers began to focus very heavily on protecting their careers, since they worried that funding cuts might leave them out of a job. And many of these senior officers understood their jobs to be similar to those that they had performed in World War II. They were not preparing for Korea or Vietnam-style limited wars. Rather, they were planning for what might happen if the Soviet Red Army busted through the Fulda Gap. As a result, the Vietnam-era Army was an institution focused on winning wars through superior firepower and technology. Westmoreland and his colleagues were trained to fight and win wars that looked like World War II, not Vietnam. They were not experts in guerrilla warfare and knew very little about Communist revolutions. Vietnam may have contradicted Westmoreland's preconceptions about how to fight a war, but he was hardly an outlier in that sense.

The Army did conduct some institutional self-reflection after the Vietnam War, but to a large degree they focused on the wrong things, and they never overhauled the discipline system for senior officers, especially generals. To be sure, the military changed a great deal after Vietnam, since it became an All-Volunteer Force in 1973. But most of the reforms concerned training for junior officers and enlisted men.

Sources and further reading:

Krepinevich, Andrew. The Army and Vietnam. Johns Hopkins, 1986.

Ricks, Thomas. The Generals: American Military Leadership from World War II to Today. Penguin, 2013.

Sorley, Lewis. A Better War: The Unexamined Victories and Final Tragedy of America's Last Years in Vietnam. Harvest, 1999, 2007.

Can you clarify what actions taken by GEN Westmoreland in you opinion came to the level of incompetence? If you are using the term OPR as office of professional responsibility then no the United States Army has never had that. Also your use of the term "we" is interesting, what division were you assigned to while in Vietnam?