In general, it pays to be skeptical of Internet polls, and the HNN one is no exception. According to the poll, 61% of historians deemed George Bush's presidency the worst in history. The author of the poll, Robert S. McElvaine, admitted that it was not scientific and that it may be too soon to make an accurate historical assessment.
While the poll may not be scientific in terms of its sample, I would argue that it was made unreliable by the way the first question was framed: is the Bush Presidency a success or failure? Frankly, if you disagreed with the outcomes of the president's policies in Iraq, or FEMA's handling of Katrina you could only answer this either or question in one way: failure. This does not even take into account the partisan ways in which you can read the terms success and failure. Finally, it would be hard to assess any president's term in office as success or failure. This should have been a likert scale type of question.
I accept McElvaine's assertion that its OK for historians to weigh in on the present administration, because they are the best equipped to compare Bush 43's legacy with his predecessors. Certainly historians are well positioned to make more detailed comparisons with the past. That said, the article was short on exactly those kinds of nuanced comparisons. The comments provided by McElvaine consisted mainly of the same generic (liberal to moderate) carping that could be had on talk radio or the Daily Kos. There were some references to other presidents, but these were not especially illuminating and generally within the reach of any local tv news anchor who had passed the US History Survey class at Moo U.
In the interest of full disclosure, I am not a republican party member or a supporter of the present administration and I voted against them in every election I could. I have no sympathy for the aims of the Bush Administration, but I am appalled by the lack of historical perspective demonstrated by professional historians who should know better. To that end I will post my own appraisal on another day.
In the meantime, duty (teaching, service, & research) calls...