I will make no brief for Howard Dean or any other national Democratic candidate - but Howard Dean's candidacy didn't fall of its own weight any more than the Soviet Union did - it was pushed! (The USSR was pushed by Ronald Reagan).What is the Dean scream? Nothing - just a moment of cheerleading by the candidate! Made to look kooky by the way it was played back in a loop, over and over. Just as if you televised someone dancing, and didn't play the audio.
The "Dean Scream" is exactly the analog of "Finally, sir, have you no shame?" in the Army-McCarthy hearings. What was that guy whining about, anyway? Unless you read Ann Coulter's Treason, you don't know what it was about. You are not supposed to know - or care - what it was about. You are supposed to just take for granted that it was an important, and justified, cry of the heart by someone who had been heartlessly abused.
All it was actually about was McCarthy responding to a heckling challenge to name some Communist - any Communist! And McCarthy pointed out that a member of the challenger's own law firm had strong connections to the Communist Party. But McCarthy was not making an unsubstantiated claim, or even a new public revelation. He was merely repeating something his challenger himself had already publicly said.
IOW, "Finally, sir, have you no shame?" was nothing but a sniveling whine, presented to the public as if it were of cosmic importance.
The idea around which liberalism coheres is that NOTHING actually matters except PR.
...which is an idea that accurately capsulizes what represents reality to the mass audience. And that's why the conservative movement's unwillingness to embrace and effectively apply the principles of PR is its greatest failing.