The alt history hypo of McCain beating Obama is interesting because it basically butterflies away both Obama moving the Democrats left, and the Tea Party moving the Republicans to the populist right.
Clearly Palin did not work out as planned. Even with a stronger running mate, McCain would have lost the race due to the financial crisis, which turned a tied election with maybe a slight Obama lead into a blowout.
But take away the financial crisis and McCain has a shot. If you're looking at winning the Hillary voters from 2008, perhaps a clearly qualified, but less charismatic, female candidate like Heather Wilson of New Mexico may have been in order. It's still very hard to get McCain to 270 but maybe a solid veep plus the financial meltdown not happening at least keeps it close.
A McCain victory that year might have looked something like this:
McCain/Wilson: 276 electoral votes
Obama/Biden: 262 electoral votes
Flip IA and NH and this is my McCain wins 08 map
