Any help he'd be in NV/NM/CO/AZ would've been balanced by anger by social conservatives in OH/PA/VA/NC who would've preferred a Santorum-esque candidate anyway.
They would vote for Obama because.........
As for turnout, if faced with the choice between a pro-choicer and an extreme pro-choicer then........
No no, I'm saying that they'd simply just not turn out.
But he's the VP nominee, not the president. Why should one issue like abortion be a deal breaker when choosing a VP?
Because this is the Republican Party.