I believe I have stumbled upon one underpinning phenomenon driving this trend. I call it "Hate Fatigue." The theory is this: the Democrats wasted their hate for George W. Bush on movies, books, blogs, meet-ups, commission hearings, and protests over the last three years and they have just about run out of steam. And now that the election is upon us, their potent venom has run dry. [...]I wrote a tongue in cheek post about this earlier. But I've found this to be a really serious problem when I've talked to people who I've tried to convince to vote for Kerry. In fact, I've found it to be a far more serious problem than the blunders of the Kerry campaign. Each of the above claims has innoculated Bush and provided powerful protection against other, potentially more persuasive criticism.
If some voters are still undecided after learning that George W. Bush is actually Adolf Hitler, knew about 911 before it happened, and alternately has Osama bin Laden in secret custody and has no interest in apprehending him at all, what more information could John Kerry possibly give them to push them over the edge?
Whereas I don't personally agree that Bush is worse than Hitler, I've followed the thought processes of those that do believe that, and I find that those thought processes are rational, given their underlying beliefs and assumptions about the world. However, the thread of logic leading to the Bush worse than Hitler conclusion starts from a different set of assumptions and beliefs about the world than those I hold, so I personally don't end up with the same conclusion. The majority of Americans don't hate Bush (his approval rating is greater than 50%) and also would not arrive at the conclusion that Bush is worse than Hitler based on their beliefs about the world and the information available to them.
That's not a problem in and of itself. People disagree on things all the time, yet remain open to persuasion in other areas. The problem with many of the meme's that the Bush hating left put forward is that they are so unbelievable and/or unpalatable to everybody else that they discredit other criticisms of Bush in the eyes of those who don't hate him. Even this wouldn't be devastating except for the sheer volume of such memes. People have been pelted by so many criticisms of Bush which they will not or can not believe, or which have been at least put into serious doubt (e.g., Dan Rather and his forged National Guard memos). At this point, everybody except the Bush hating left assumes that all criticisms of Bush coming from democrats and the left are suspect.
This situation has been compounded by the fact that many from the left consider anyone who disagrees with their conclusions as stupid and are very vocal in their insults. Even worse, many on the left are so frustrated with the rest of the "stupid" people that they are not even willing to engage in conversation with them.
So we have the left putting forth non-credible criticisms, calling everybody stupid for not believing them, and then refusing to continue the conversation about topics that might persuade voters to vote for Kerry. As a result, Bush has been successfully innoculated from criticism from the very people who most want to unseat him.