What if John McCain had picked Joe Lieberman as his running mate in 2008?
I'm thinking that in late 2006 or early 2007, Lieberman opts to caucus R for some reason - forcing the Senate into a tie and making Cheney the tiebreaker. Lieberman's newfound popularity on the right enables McCain to get away with picking him as his veep come 2008.
How would this change the character of the race? I think McCain-Lieberman would hammer a lot harder on National Security. There'd also possibly be an early acceptance that GOP base turnout would be weak, and McCain might focus more on swing voters.
Older Jews in Florida had a tough time with Obama considering HRC hammered him hard in the primary on Israel. I could see McCain making gains in Florida.
North Virginia security voters might swing towards McCain more.
GOP base turnout being weak could have a colossally bad impact on downballot races. McConnell and Chambliss come to mind as folks particularly vulnerable.
Given how close Missouri and Montana were, Obama might take them here.
The Tea Party movement, assuming it still pops up, will have a galvanizing figure other than Palin here. Ron Paul maybe?