Can Mitt Romney win the White House without carrying Ohio? Yes, but it's a very hard road.

The New Yorker's John Cassidy says, with Barack Obama seemingly solidifying his lead in Ohio, Romney's path to 270 electoral votes gets much narrower. Romney would have to win Florida, Virgina and Wisconsin or Colorado, Iowa, Nevada and New Hampshire. Either of those outcomes would require a big shift in swing state polling with just a week to go in the election.

For the sake of argument, let's assume that Obama ends up holding onto Ohio. Does that mean Romney is out of it? Not completely. But to reach two hundred and seventy votes, he would need to turn around three or four blue states, which doesn't seem likely without another swing in his direction nationally.

It's a good story line, which some of the media will run with, but I don't quite believe it. In 2008, Obama carried Wisconsin by fourteen points. Since Labor Day, more than a dozen polls have been carried out there, and Romney has yet to lead in one of them. (Friday's Rasmussen poll is the only survey to show a tie.) Still, Obama's average lead in the five polls carried out during the past two weeks is only 2.2 per cent, which is narrow enough to make it interesting, especially with Ryan on hand to rally the G.O.P. voters, and Tommy Thompson, who served four terms as governor, running for the Senate. As a result of the failed attempt to recall Governor Scott Walker, in June, both parties have extensive ground operations.

The arithmetic is tricky, but the overall message is clear: Without Ohio, the math is forbidding, though not completely prohibitive, for Romney. But even if he doesn't defeat Obama, couldn't he somehow manage to get a tie? Actually, he could. Let's assume, once again, that the G.O.P. candidate carries Florida and Virginia, taking him to 248 votes in the electoral college. Now imagine that he fails to win Ohio, or New Hampshire, or Wisconsin, but somehow ekes out victories in Colorado (9 votes), Iowa (6), and Nevada (6). That would take him to 269 votes. Obama would have the same number. The result would be a draw. According to the Twelfth Amendment to the Constitution, the House of Representatives, which almost certainly would still be under Republican control, would then choose the next President. Romney could end up sitting in the Oval Office, after all.