The Matthews moment means that it may be, might be harder in the future to use such analogies so far out of context. He created an opening to challenge the deployment of such broad analogies and labels, and has forced those who want to use labels such as appeasement to augment their statements by adding the offending act. Now, this could all be for naught, if everyone lets it drop, but it could also be a subtle but important shift in the way this powerful label is used. To pass the Matthews test, anyone on his show now needs to show the dangerous concession. Matthews had defined a rhetorical space in which simply talking to another actor cannot constitute appeasement, and anyone who tries to suggest as much will look like a fool.
Now, this is by no means guaranteed. Matthews could let it drop (but I doubt it, given his tenacity on issues such as this). Moreover, MSNBC has become a much more important player in election coverage (really, its gotten quite good. Olberman is in rare form, Matthews is always fun, and its impossible to top Rachel Maddow). So, if Obama’s opponents want to deploy the appeasement label for him, they are going to have to figure out how to go on Hardball and make it stick. Otherwise, the attack loses some of its steam.