Don't think for a minute that the American Left is in a constant state of protest againt Abu Ghraib, Gitmo, Afghanistan, Iraq, etc. because they are utterly concerned with the gravest of humanitarian circumstances (see Zimbabwe, Cuba, Sudan, Niger, N. Korea, India...). No, their opposition stems from their lifelong dedication to the denial of any rightousness of the American Right or justification of its ideals and methodologies. To the Left, President Bush is the iconic reminder of all that is evil about the Right. Long before Mr. Bush met with his presidential exploratory committee in the mid-90's, before Iraq Invasion Part 2, before Afghanistan, before 9/11, before World Trade Center Part 1 (1993), and even before Slick Willy turned the prestigious presidential dwelling into his personal frat-house/brothel, the scene was set. Whomever the Right put in the White House and regardless of what evil they were doomed to confront in the 20th century, the Left had already positioned itself in opposition.
You see, the "American" Left is preeminently anti-Right rather than pro-America. After all "American" ideals such as equality, perseverence, opportunity, and the willingness to confront evil anywhere it exists, regardless of whom it directly threatens, are of no real concern to the Left. They'd just as well see America collapse than terrorism defeated. For nearly 100 years, this irrational discontent for American righteousness has plagued the Left, but it has become even more apparent recently that they are putting politics before everything, including that one endeavor which may be the most significant for the survival of human society: humanitarianism.
Christopher Hitchens, a left-leaning idealogue, explains the Left's weaknesses and utter hypocrisy in his recent Letter to the Left.