From an NPR story this morning on Mitt Romney's attacks on President Barack Obama in Ohio:
Across town at Shorty's True American Roadhouse, Michelle Maziarz has seen that improvement. She and her husband are taking their two young kids out for barbecue. "Around here, a lot of people work at the auto plants. … Both my parents work for Jeep [a Chrysler product]. And I can tell you, like a year ago from today, no one was getting overtime or anything like that, and now you're starting to see third shift come back." Business is picking up at the mall where she works, but she doesn't give this President credit. "I give that to our city, that credit goes to our city. … That's our people, in our community." She does not think that Barack Obama will get her vote again. [Emphasis added]
The United States chooses a president through the Electoral College, but that doesn't mean that we ought to pay the most attention to state polls; national polls are often reflective of what will happen on the state level. If Romney were to suddenly make a five-point gain in national surveys, you would see a corresponding shift on the state level.
The relationship between voters and the economy is similar. State-by-state economic performance is less important than national performance, since voters are more likely to evaluate the president on account of national conditions. For that reason, the NPR quote is illustrative; the auto bailout-a decision made specifically by the president-literally rescued her town from economic stagnation. But she's evaluating Obama on the basis of the broader economy, and he's lacking.