I made a comment describing the phenomenon here:

https://sh.itjust.works/post/23959648/13416196

(Sorry, I don’t know the proper way to link a comment in an instance-agnostic way so I linked to the URL of my home instance)

That’s confusing cause and effect. Howard Dean’s speech was supposed to be a concession speech after losing the only early primary/caucus he was trying to win. He poured in all of his resources in the hopes of winning Iowa, underperformed expectations against a backdrop of dropping in the polls for weeks, and coming in third (with no real prospects for New Hampshire or South Carolina) basically made it impossible for him to have the volunteers, money, or press coverage to survive into the next stage of competing in bigger states with primaries clumped up together.

He showed everyone his plan of winning Iowa or going home, lost Iowa, and then gave some kind of rallying speech as if he had a plan to recover from that loss. He never did, and it wasn’t the scream that killed his campaign. His campaign was dead before the scream happened. It’s just that the scream was a particularly memorable way for a campaign to die.