Also, for those who like to go more in-depth - here is a full book, published by the Air Force itself in 1986, with a very thorough assessment of Rolling Thunder:
http://www.dtic.mil/get-tr-doc/pdf?AD=ADA215903 (pdf link from the DoD's Defence Technical Information Center)
The Vietnam War was many things to many people. It represented, among many other things, the clash between the views and objectives of American's civilian leadership and traditional military doctrine. It illustrated the difficulty in prosecuting a conventional war against an unconventional enemy and in waging a limited war against an enemy waging an essentially unlimited war. The Rolling Thunder campaign, the longest sustained aerial bombing campaign in history, was a microcosm of the problems the United States faced in the war as a whole. American air power doctrine was based on the concept of strategic bombardment, a concept based on two fundamental assumptions: that any American war would be waged to destroy the enemy's ability to wage modern warfare, and that any enemy the United States might engage would be a modern industrialized state. In Vietnam, neither assumption held true. The resulting aerial campaign, Rolling Thunder, was a far cry from that envisioned in plans developed before the American intervention. This study illustrates how American air power doctrine developed in a manner incompatible with the employment required over North Vietnam and how even the best military advice can be ignored if it does not conform to the objectives of the civilian leadership. Moreover, the study indicates that even if the military had been allowed to carry out its desired intensive bombing campaign, the results might not have changed. Finally, the study indicates the problems inherent in developing effective air power doctrine across the spectrum of modern conflict.