Vettel is still fast as crap, but he has not been the same since Germany. With the exception of Spa, Vettel has been outdone either by questionable team strategy or his own undoing. Meanwhile, Hamilton has been in peak form, even more so than after the summer break last year. Besides Spa (where he may have been better letting Vettel ahead on the first corner then using the tow up Eau Rouge) and last week's team orders (which sucked, but still) he's been dominant the 2nd 1/2 of the season (his win in Shanghai was quite impressive).

Unless there's a catastrophic breakdown Hamilton can wrap this up in Austin once again. Even if he doesn't, Vettel would need to win out the rest of the season and hope Hamilton doesn't make another podium.