Battleground states, by definition, have lots different groups and regions that balance each other out to an almost-even split, especially when an election that looks as close as this one does. Small shifts in any can tip a whole state.
State-by-state, we'll explain the ways you'll be able to tell whether President Obama or Mitt Romney is doing well as the returns come in on election night -- the key regions, counties and groups to watch, and why.
It is no accident this is the Obama campaign's firewall and a key state in this race. Filled with the kind of working-class, middle-class voters that the Obama campaign is targeting, if Mr. Obama cannot hold on to the faster-growing boom states like Virginia and Colorado, then he has to make a stand in places like Ohio and Wisconsin. Ohio may not be a microcosm of the U.S. any longer but it is representative of America's industrial heartland - and a mix of large cities and suburban and small towns adds up to a closely divided state.
Signs Mr. Obama is doing well:
- First and foremost, few things matter to Mr. Obama's chances more than the raw vote numbers around Cleveland. This is step one in the Democratic strategy for winning Ohio. Mr. Obama would like to take around 250,000 more votes out of the county than Romney does, and if he doesn't, it gets harder to make up that margin elsewhere in the state.
- He's winning the Columbus area. This is something of a "swing" region. (And by region, here as elsewhere in these documents we mean the group of counties clustered in an area. Using regions allows us to get a better handle on overall trends than looking only at one single county.)
- Nearby, he'd like to get above 52 percent in eastern Ohio, including the areas around Akron and Canton - these are usually Democratic areas where working class voters hold sway, and a key part of his coalition. Often, Democrats who only break even here can lose statewide.
- He keeps it close in Northwest Ohio and gets big margins around Toledo. He's got to take 60,000 to 70,000 vote margins out of Lucas County (Toledo) and that may speak to how well the auto bailout played for him.
- He's winning or even among working-class white voters.
- Young people are turning out (they were 17 percent in 2008) and backing him with over 60 percent of the vote. For Mr. Obama in 2008 it was as much about vote swing as turnout among under-30 voters, he did six points better than Kerry. He has to again.
- He's close - even if not winning - in the white vote. If he gets 45 to 47 percent he stands in good shape, repeating '08 levels. Lower and he'll have to make it up with turnout elsewhere.
- African-American turnout is 10 to 11 percent of voters. Lower and he faces a problem.
Signs Romney is doing well:
- He's winning the Columbus area. It's a swing part of a swing state; Obama won it, Bush won it.
- He's winning college-educated voters back (Republicans lost them in 2008). Upper-income and college voters in Ohio don't tend to be as liberal in Ohio as they are on the coasts.
- He's got solid majorities in suburbs around Cincinnati, especially Butler county (where Romney will aim for at least 60 percent or more) and the counties nearby. This is usually Republican territory as has been for a long time. Obama cut into it in 2008, but will have a hard time repeating that.
- He's getting at or above 56 percent in small town and rural areas throughout the state. Obama held down typical Republican margins in such places last time. Romney should be able to run them back up again.
- He's winning or even among white working-class voters earning under $50,000, which would be cutting Obama's margins slightly from '08. If Romney can win or hold even here it would be a sign his campaign has countered negative views of Romney among working class groups.
Next page: Florida