Ohio is one of 10 states holding contests to pick their party's presidential nominee on Super Tuesday, but it has been the main focus of attention for GOP candidates because it will be a major battleground state in the general election this November.
The conventional wisdom has been that whoever takes Ohio in the general election goes on to win the White House, which gives Tuesday's contest a lot of potential momentum for the eventual winner.
If Rick Santorum has a lead on Mitt Romney in Ohio, it looks like it's not much of one. A new Quinnipiac University poll shows Santorum leading Romney by four percentage points, 35 percent to 31 percent.
With the margin of error at +/-4.3 points, the two top rivals for the Republican presidential nomination are essentially tied just days before Super Tuesday when voters in Ohio and nine other states take part in the presidential primary process.