I’ll grant Barr probably cost McCain Indiana, but I also think he took the state for granted. I’m looking at populous Allen County in the northeast, home of Fort Wayne, it went for Bush 63%-36%, but only went for McCain 52%-47%. The state really shouldn’t have been close enough for any third party candidate to cost McCain the win (or for that matter, vote fraud).
Contrasting that with OH, which McCain lost by 51-47%, his targeting the state actually improved upon Dubya's performance in a whopping 64 of 88 counties, including Cuyahoga (Cleveland), Summit (Akron) and Montgomery (Dayton). Only the northwest corner, the Columbus & Cleveland areas and an isolated area in the NE went the other way.