Ohio is (almost) the whole ball game in today's presidential election.  If President Obama wins it, he's a near-lock to win a second term. If Mitt Romney wins it, his prospects of upsetting the incumbent go from iffy to strong.

When we broke down the most likely path to 270 electoral votes for Obama and Romney, the only -- yes, only -- difference between the two maps was Ohio.

Given the primacy of the Buckeye State to both Obama and Romney, we thought it was worth digging back through the voting history of the state to find some clues about how the state might go tonight.

Below are the three maps and one chart that we found most interesting.

1.  Here's a look at the vote for the parties' presidential candidates in the past eight elections in Ohio.  Looking back at just the last three presidential elections in the state, the Democratic nominee has averaged 48.66 percent of the vote while the Republican nominee has averaged 49.23 percent. So, yeah, the state is pretty evenly divided.

2. If Romney is going to win in Ohio, his blueprint for victory will look a lot like the map George W. Bush used to carry the state with 51 percent in 2004.  Here's the Bush map -- courtesy of the University of Akron's Center for Policy Studies.

3. Looking for the bellwether counties in Ohio? Take a look at this map from the Cleveland Plain Dealer that breaks down the swing counties in presidential race from 1992 to 2004.  Those counties: Wood, Carroll, Tuscarawas, Guernsey, Perry, Pike, Hocking, Vinton, Meigs, Lawrence and Scioto. The swing counties tend be clustered in the southern and eastern portions of the state.

4. This map -- from the good folks at the Center for Politics at the University of Virginia (Go 'Hoos!) -- sizes each of the counties in Ohio based on vote totals. The larger the county, the more votes came out of the county in 2008.