As of late Tuesday night, it appears the outcome of the election is becoming clearer. As Robert Barnes reports:

President Barack Obama was on the verge of winning a second-term Tuesday night, defeating Republican Mitt Romney in a series of close battleground state contests, according to network projections.

Some prizes--Florida, Ohio and Virginia--were still too close to call, but there were encouraging signs for Obama because of still-to-be counted votes in Democratic strongholds there.

Earlier in the day, while the final outcome of the 2012 presidential election was thought not likely to be clear until late Tuesday night or Wednesday morning, exit poll information was useful in projecting forward, as Sarah Kliff writes for Wonkblog:

It’s hard to divine when polls will prove accurate – and when they’ll lead election watchers astray. Pollsters do, however, have a few tips on how to make the most of election polls. 

The first rule of exit polls is this: Before 5 p.m., there are no exit polls. That’s when the “quarantine” lifts on the exit poll data, collected by interviewers stationed at polling places across the country, that major television networks use to project outcomes.

“Given the precautions we take, the chances are infinitesimal that you’ll see correct information before 5 p.m.,” says Larry Rosen, president of Edison Research, which runs the exit poll that the major networks and newspapers use (The Washington Post is among the newspapers that has paid for access.) 

It’s not like the floodgates open at 5 p.m., either: Networks are prohibited from releasing information that could be used to project the race until after polls have closed. It won’t be until 7 p.m. that projections get the green light on the East Coast.

At that time, as Scott Clement writes for the Fix, more information should start to trickle out:

Virginia polls close and preliminary vote breakdowns start to emerge (7 p.m.):  Don’t expect projections at poll closing in competitive states, but soon afterward look for a wave of information about vote breakdowns by group. Keep an eye on the heavily Democratic Northern Virginia as well as the Republican-leaning south and west portions of the state.

More exit polls, and a bit of advice (8 p.m. and beyond): The exit poll numbers will change. Because the exit poll weights their data to match vote totals when they become available, a double-digit lead for Obama among women could shrink to single digits, or no lead at all, later on in the night. Even after that, remember that the exit poll is still a poll, with a margin of error to boot. The margin of error balloons for vote results among small groups, such as Hispanic voters, Jewish voters and voters under age 30.

However, according to Washington Post politics reporter Bill Turque ,it’s possible that the results of the race could take more than one night to play out:

There is a decent chance that by the time most Americans wake up on Wednesday morning, the seemingly endless campaign will finally have ended. But all the elements are in place for a Florida-style donnybrook of recounts, lawsuits and partisan intrigue. Pivotal Ohio is a tossup in many polls and at the center of most overtime scenarios. State law provides for an automatic recount if the margin separating the candidates is within one-quarter of a percent of the total votes cast. But before any recount begins, each of the 88 county election boards has until Nov. 27 to certify results and submit them to Secretary of State Jon Husted. Unless he decides to expedite the process, a recount would be unlikely to begin before early December.

The state has a history of Election Day troubles, and this year could be a logistical nightmare. Husted decided to have absentee-ballot applications mailed to 7 million registered voters. So far, about 350,000 residents who requested the ballots have yet to mail them back. If they decide instead to vote in person on Tuesday, they must use provisional ballots — a precaution against double voting. Officials could be inundated with provisional ballots, which must be evaluated individually. At the center of it all is Husted, a Republican who has drawn criticism from Democrats for his attempts to limit early voting. Under Ohio law, the secretary of state is given unusually broad power over elections, and Husted could play a critical role in determining the next president.

In a separate piece, Turque and fellow reporter David Fahrenthold write even further on Ohio’s potential role in drawing out the final result of the presidential race:

On Tuesday night, parsing the early returns from Ohio could be confusing. In the first minutes after polls close, the state is likely to tally up the returns from early voting. These are expected to break heavily for Obama. After that, Romney should creep closer, since he is expected to do better among those who vote on Election Day.

By the time all those votes are counted, the winner still may not be clear. If the number of provisional ballots cast is greater than the number of votes that separate the two candidates, then there could be a long and heated battle over which provisional ballots to count.

Chris Cillizza and the Fix team have a great guide to when the polls close in different states — from Indiana at 6 p.m. all the way to Hawaii at midnight. Check out their rundown to find out what information you can expect (and when) throughout election night. Also keep an eye on The Washington Post’s 2012 election map, which will start showing live election results for each state and county as of 6 p.m. ET.