Suppose the ticket were Michael Bloomberg and Evan Bayh, or Olympia Snowe and David Boren. If the Republicans nominate Romney, wouldn't the Americans Elect ticket take more votes from him than from Obama?
I don't know if the Koch brothers specifically are helping to fund this, but what I've heard does suggest that most of the money is coming from the right. That leaves me wondering what the real agenda of this organization is.
Here's what I see as the best scenario for us: Regardless of the intentions (and machinations) of the founders and funders, the "online primary" is sufficiently open that the participants can wrest control from the hierarchy and nominate their preferred candidate. Their preferred candidate turns out to be Ron Paul, because his enthusiastic supporters flock to Americans Elect when his Republican campaign peters out. Paul, enticed by the prospect of easy ballot access everywhere (or with only a few exceptions), therefore decides to run in the general election, as he's done once already. With a 50-state Ron Paul candidacy in November, Obama wins more electoral votes than he did in 2008, even if the economy takes a bad turn.
I suspect that the powers that be at Americans Elect will prevent this from happening. That still leaves me wondering what their actual plan is, though.
If they really wanted to screw Obama they'd arrange to nominate someone like Rocky Anderson, hoping that he could be the Ralph Nader of 2012. I don't see how they could pull that off, though, given all their hot air about centrism.