The race in Pennsylvania continues to tighten, with ABC News switching the state from solid Obama to lean-Obama in its electoral map. Both campaigns are pivoting back to the state, and Politico reports that the Romney campaign is reserving ad space, on the heels of a $2 million ad buy by pro-Romney super PAC Restore Our Future and a $600,000 American Crossroads purchase.

Romney’s ad, a $150,000 buy from Nov. 5-6, hits Obama hard on coal: 

ABC notes the campaigns have hit the saturation point on ad buys in Ohio and Virginia, and Pennsylvania is one of the few states where more ad spending can matter. Still, the fact that the Obama campaign is funneling resources there in the final days is telling, considering the state was supposed to be a safe one for them.

The Romney campaign released a memo today emphasizing its efforts in Pennsylvania:

Pennsylvania presents a unique opportunity for the Romney campaign.  Over the past few years we have seen Pennsylvania voting for a Republican senator and a Republican governor, and Republicans win control of the State House in addition to the State Senate. The western part of the Keystone State has become more conservative (and President Obama’s war on coal is very unpopular there), and Mitt Romney is more competitive in the voter-rich Philadelphia suburbs than any Republican nominee since 1988. This makes Pennsylvania a natural next step as we expand the playing field.

The Romney campaign is expanding the field while the Obama campaign is just trying to hamper its losses. Obama still has a clear lead in the Pennsylvania polls, 4.7 percent in the RCP average, but that’s down from an 8-to-9-point lead in September. And that was without a major ad blitz. Romney may not be able to close that gap in a week, but he can make the Obama campaign divert money to the state that it otherwise would have been spending elsewhere.