Just how much has this race changed since the first debate in October?  At the time, Democrats thought they had a pretty good glide path to a narrower win in the Electoral College than in 2008, but a win nonetheless.  Almost four weeks later, the Obama campaign is having to buy air time in states previously considered safe, such as Pennsylvania and Minnesota, the only state that never voted for Ronald Reagan in the EC.  Mark Halperin tells Morning Joe that while one cannot claim to know how this race will turn out, there is no doubt now that the Democrats have gone onto the defensive in states that they absolutely cannot afford to lose:

For corroboration, here’s Chuck Todd noting that Team Obama has now begun buying ads in the Keystone State:

It's official, both Obama campaign and Xroads are on the air in PA. Spending figures coming soon.

— Chuck Todd (@chucktodd) October 30, 2012

If Obama has to personally start campaigning in Pennsylvania, Halperin says, that’s a problem in another way.  “Every day they’re spending in Pennsylvania,” he notes, “is a day they’re not spending in Ohio.”  And Team Romney is starting to like the way the race is turning in Ohio, Byron York reports:

Jason admits he didn’t pay much attention to politics four years ago. Since then, though, he’s been repeatedly disappointed by Obama. He was leaning toward Romney but still undecided until the first debate in early October. That did it; like his wife, Jason is all in for Romney now.

Gloeckner has joined what appears to be a growing number of Ohio voters moving toward a vote for the Republican ticket. On Monday, pollster Scott Rasmussen released a new survey showing Romney leading Obama in Ohio 50 percent to 48 percent — the first poll to show the challenger in front. Over the weekend, a poll done for Ohio’s top newspapers showed the race dead even, with both candidates at 49 percent.

Of course, many polls have shown Obama with a slight lead in Ohio, but the newer surveys suggesting a tightening race have Romney forces confident that something is going on in the state. On Monday morning, the campaign sent out a new strategy memo from Scott Jennings, the Ohio campaign director, that used the word “momentum” six times. Team Romney sees it everywhere in Ohio: polls, endorsements, early voting.

We’ll see.  But if Obama has to start defending Pennsylvania, that speaks volumes about his traction in more-Republican Ohio.