Yes. Romney was leading in the national popular vote for a while before the election. We saw how NV, CO, IA, WI, OH, NH, VA and FL were all within reach for Romney.
The national polls underestimated Obama though. Obama won NV by 7 points, CO by 5 points, IA by 6 points, WI by 7 points, OH by 3 points, NH by 6 points, VA by 4 points, and FL by 1 point. Remember Obama won the popular vote by 4 points, so he had a notable advantage in the Electoral College.
Romney pick of Ryan is probably the worst vp choice ever when it comes to political impact(McCain wouldnt have won after Lehman) as Ryan's views on entitlements cost Romney FL and didnt help him at all in key Rust Belt states like OH and PA. That made Romney's path to 270 extremely narrow that entire cycle which allowed Obama to play on offense the entire cycle .
Romney should have picked Portman, as if he picked Portman he very likely wins FL and OH which would put him at 253 and Obama would have to put in lots of resourced to defend PA as well which then he couldnt use on states such as VA , IA , CO and Romney could play offensive in those states.
Portman also would faceplant in the VP debate which halted much of the momentum the Romney camp had after the 1st debate
I think if Romney chose Portman as his vp he would have won
