Would Obama have won Arizona if McCain wasn't running?

Sean Quinn's post about the Mountain West at the ever excellent FiveThirtyEight got me pondering the question of whether Barack Obama would have won Arizona if John McCain hadn't been his opponent.

The answer based on my very simplistic analysis is yes. I looked at the difference between the 2004 and 2008 vote for each of Arizona's neighbors:

State	2004 Vote	2008 Vote	Difference
California	D+10	D+24	D+14
Colorado	R+5	D+9	D+14
New Mexico	R+1	D+15	D+16
Nevada	R+2	D+12	D+14
Utah	R+46	R+29	D+17

The trend in those five states is remarkably similar, with Barack Obama doing on average 15 points better than John Kerry did and all of them falling within the 14-17 point range.

George W. Bush won Arizona by 11 points in 2004 so it stands to reason that if Mitt Romney or Mike Huckabee had ended up as the GOP nominee instead of McCain, Obama probably would have won the state by 3-5 points if its behavior had fallen in line with all of its neighbors. That tight margin would have easily made it the closest state in the region.

Given the significant gains Democrats have made in the state's Congressional delegation of late and the movement in surrounding states in the Presidential election this year I think you can expect Arizona to be near the top of the list of swing states in the next few cycles.