I think that Ann Althouse is missing the boat on her fisking of Obama's "Honor" ad. This ad has an audience of one, John McCain. McCain's famous for holding his honor in high regard. He moved mountains to erase the stain of being caught up in the Keating Five scandal. He's also famous for his temper. Being called dishonorable like this isn't going to directly move a lot of voters. It's too crude, too 'in-your-face' to move the undecideds. But if McCain loses his cool, if he goes into a sputtering rage in defense of his honor, now that would move independents.
Every other effect of this campaign is incidental. Obama's banking on being able to break McCain psychologically. If Obama's campaign can do it, McCain's not the same man who withstood the N. Vietnamese interrogators so well. But I don't think Obama can, no matter how low he goes.