On Wednesday, Republican presidential nominee Mitt Romney dismissed concerns over a recent glut of bad swing-state polling that has left him in trouble in the near must-win: Ohio.

"I’m very pleased with some polls, less so with other polls, but frankly at this early stage, polls go up, polls go down," Romney told ABC's David Muir after a day of round-the-clock campaigning in the Buckeye State.

Romney will spend the next 40 days campaigning there tirelessly, because the state offers him one of his few clear paths to electoral college victory. Though he only trails by an average of 4 points in national polling, he'll be hard-pressed to pick up the electoral college votes he needs without Ohio.

With that in mind, we took a look at where Romney is facing the biggest challenges — and what happens if he doesn't overcome them.