If you don't read the whole Sean Wilentz profile of Bush's "presidency," at least read these two paragraphs:
http://www.rollingstone.com/news/profile/story/9961300/the_worst_president_in_history?rnd=1145468541266&has-player=true&version=6.0.8.1024How does any president's reputation sink so low? The reasons are best understood as the reverse of those that produce presidential greatness. In almost every survey of historians dating back to the 1940s, three presidents have emerged as supreme successes: George Washington, Abraham Lincoln and Franklin D. Roosevelt. These were the men who guided the nation through what historians consider its greatest crises: the founding era after the ratification of the Constitution, the Civil War, and the Great Depression and Second World War. Presented with arduous, at times seemingly impossible circumstances, they rallied the nation, governed brilliantly and left the republic more secure than when they entered office.
Calamitous presidents, faced with enormous difficulties -- Buchanan, Andrew Johnson, Hoover and now Bush -- have divided the nation, governed erratically and left the nation worse off. In each case, different factors contributed to the failure: disastrous domestic policies, foreign-policy blunders and military setbacks, executive misconduct, crises of credibility and public trust. Bush, however, is one of the rarities in presidential history: He has not only stumbled badly in every one of these key areas, he has also displayed a weakness common among the greatest presidential failures -- an unswerving adherence to a simplistic ideology that abjures deviation from dogma as heresy, thus preventing any pragmatic adjustment to changing realities. Repeatedly, Bush has undone himself, a failing revealed in each major area of presidential performance.