Voting in the 2012 election is underway. And yes, you read that correctly.

Several states have already begun accepting completed absentee ballots, and in-person early voting has even begun in three states: South Dakota, Idaho and Vermont. As for the swing states, absentee ballots are already being returned in North Carolina, Wisconsin, New Hampshire and Virginia, while in-person early voting starts in the first swing state, Iowa, on Thursday and another, Ohio, next Tuesday.

What does it all mean? It means the votes that count in the 2012 election are already being cast. And that means we've finally got some hard data to start gauging who has got the inside track on the White House.

That's because some of these states (God love 'em) provide a party breakdown of the early vote, which can be gleaned for clues about which side is turning out more of its base.

So from now until Election Day, The Fix will be providing regular updates on how many Democrats and how many Republicans are voting early in these key states and what it says about the race ahead.

The chart above (which we will replicate in every update) provides several key pieces of information related to early voting in swing states, including the start dates for absentee and early voting, how many voters voted early in 2008, and how the early vote has broken down by party in 2008, 2010 and thus far in 2012.

(The data above are culled from a couple must-have sources for early voting data, including and the United States Elections Project of George Mason University's Michael McDonald, who is doing yeoman's work in pulling updates on the party breakdown of the early vote across the country.)

A couple notes on how to keep tabs on the early vote:

1. Early voting is very important.

Many swing states now feature huge chunks of their electorate voting early, with two-thirds of voters voting early in Colorado and Nevada in 2008 and more than half voting early in Florida and North Carolina. And early voting is expected to rise in basically every state this year. These numbers matter — a lot.

2. Democrats generally vote early more than Republicans.

In the five 2012 swing states where a 2008 early voting breakdown is available, Democrats voted early more than Republicans in all five. Even in a very good GOP year in 2010, Democrats voted early more often than Republicans in North Carolina, Iowa and Nevada.

3. Keep it in perspective.

When looking at the early voting breakdown in a given state, it's important not to just look at which party is voting early more, but how that breakdown compares to recent elections. In North Carolina, for instance, Democrats held a 21-point early voting advantage in 2008 but they barely won the state. (The GOP also made huge gains in the Tar Heel State in 2010 despite losing the early vote by 10 points.) So the name of the game for North Carolina Republicans is not winning the early vote, but rather shrinking the gap from 2008.

4. Party breakdown isn't a perfect gauge.

Party breakdown tells us the party affiliation of who is voting early, but it does not tell us exactly how those ballots are being cast. Just because a Democrat voted early doesn't mean he or she voted for President Obama, and the same goes for Republicans and Mitt Romney. It also doesn't tell us anything about how the all-important independents might be voting.

5. We don't know much yet.

So far, the only swing states where we have any real data are North Carolina and Iowa, and those data are very sparse and only absentee numbers. Slightly more than 6,000 absentee ballots have been returned in North Carolina, with Republicans returning 47 percent of them and Democrats returning 34 percent, according to McDonald's totals. McDonald also notes that, of the 66,000 absentee ballots requested so far in North Carolina, 51 percent went to Republicans and 28 percent went to Democrats. We need to emphasize, though, that much of the Democrats early voting advantage comes from in-person early voting and not absentee voting (which generally leans Republican), so this absentee data is only a little helpful.

In contrast, Democrats have a huge advantage in early absentee ballot requests in Iowa, 67 percent to 12 percent (out of 158,000 requested). The data in Iowa and North Carolina paint very different pictures at this very early juncture and reflect the fact that we simply need more data to start drawing broad conclusions.

Stay tuned to The Fix for all the latest on early voting. We'll be revisiting this throughout the next six weeks.