I think he was beatable, but Rs ran the wrong campaign against him. By late October after Sandy it was pretty much over. Romney narrowly won the persuassion argument, but Obama was able to mobilize his voters where it mattered. Obama's win in Ohio 2012, is arguably the most impressive win of the 21st century even more so than Trump cracking the blue wall.
It's really interesting Ohio is seen in that way from today's perspective. I remember back in 2012 it was more of "the ultimate battleground" and Obama winning not a huge surprise.
Its really how Ohio swung compared to every other rust belt swing state.
Michigan->R+6
Wisconsin->R+8
Illinois->R+9
Indiana->R+10
Pennsylvania->R+6
Yet Ohio only swung to Romney by 1.5 and even trended slightly left.
