I've been thinking about Colin Powell. His endorsement of Obama in 2008 was a big, big deal. Despite the nicks and worse he's taken over that infamous UN briefing, he still seems to have a great reputation among Americans, so his endorsement will mean something.
I'd reckon that Powell is waiting for tonight, since foreign policy is his bag. Then maybe we'll hear from him on one of the Sunday shows. I've seen no reporting on this, but we can assume both campaigns have been sending him pizza and other goodies for months.
Obviously, if he endorses Romney, that would be pretty devastating to Obama. He'd have to talk about his disappointments with Obama, although I don't know what those would be, but such a move would really hurt Obama.
On the other hand, if he endorses Obama, well, it depends on how and how strongly, and what he says about Romney. He can use language signaling that Romney is also okay, or he can say in essence that Romney would put the war mongers back in power. I think he's still the most powerful single endorser in the country, probably.
Any competition for that title you can think of?