UPDATE, 9p ET: Fox News can now project that President Barack Obama will win in the battleground state of Pennsylvania. Take a look at the standings below:

Get continuing updates on the standings of Mitt Romney and Barack Obama in the state of Pennsylvania, with latest polls, political facts, figures, stories and commentary.

8p ET UPDATE: Polls have closed in Pennsylvania, but the race remains too close to call.

Update: Issues at the polls are being reported in Pennsylvania this morning. Click here for more on that, including a New Black Panther Party member again patrolling a voting location in Philadelphia.

Current Standing Among Likely Voters:
Barack Obama: 49.4%
Mitt Romney: 44.8%

Poll Times:
Open: 7:00a ET
Close: 8:00p ET

2008 Election Results:
Obama - 3,276,363 votes - 54.65%
McCain - 2,655,885 votes - 44.30%
Other - 62,889 votes - 1.05%

The 2012 race will test the state’s long-term role as a battleground. Pennsylvania remains a battleground state, but has steadily trended Democratic.

The state offers 20 Electoral College votes and has been competitive up until Election Day in every presidential campaign for the past few decades even though it's voted Democratic in every race from 1992 on. No GOP nominee has won it since George H.W. Bush in 1988.

Obama looks to be on track to keep the Keystone State in his column, as polls consistently show him ahead of Romney.

Republican groups tried to make the state competitive for Romney this year by running ads early on.

But, in the end, Romney isn't aggressively competing in the state. Romney has only nominally campaigned in Pennsylvania for the general election, as he struggles to narrow Obama's advantage with white working-class voters and women. Despite Romney having 24 campaign offices in the state, registered Democrats outnumber Republicans by roughly 1 million and Obama leads in polls.

With 20 electoral votes -- more than Ohio, Virginia or North Carolina -- Pennsylvania often beckons to Republicans then disappoints. McCain campaigned in Pennsylvania four years ago but lost by 11 percentage points to Obama.

The state often looks tantalizingly competitive to GOP strategists, who usually start off hoping to compete in Pennsylvania. But at the end of the day, they usually find it a mirage.

Between his first inauguration and the presidential election of 2004, George W. Bush paid no fewer than 44 visits to Pennsylvania, a battleground state that he was determined to deny to his Democratic opponent, Kerry. So fierce was his ardor that, late in the campaign, he found time to fly to rural Lancaster County, there to meet and woo the straw-hatted, horse-and-buggy-driving Amish. In vain: Kerry won Pennsylvania, albeit by only 144,000 votes out of almost 5.8 million cast.

While the 2000 national election split the country almost down the middle -- Gore beat Bush in the popular vote by one-half of 1 percent -- Pennsylvania went for the Democrat by more than 4 points.

Four years later, with Bush winning reelection over Kerry nationally by almost 2.5 points, Kerry was carrying Pennsylvania by virtually the same margin. And in 2008, Pennsylvania performed about as it had in the two previous elections. While Obama won nationally by just more than 7 points, he carried the Keystone State by a little more than 10 points.

In other words, over the past three elections, the state has been 3 or 4 points more Democratic than the nation as a whole.

Yet the state is more finely balanced than its voting record and registration would suggest. Reasons include population shifts out of the big cities; a hardening of conservative views among working-class “Reagan Democrats” in the state’s south-west; and a history of ticket-splitting.

Republicans made gains here in 2010 by winning the governorship, several House seats and a highly competitive Senate contest.

Registered Democrats still outnumber Republicans in Pennsylvania. But Rob Gleason, chairman of the Republican Party of Pennsylvania, pointed to GOP gains in the 2010 election as evidence that the state is now "a little more red than people might think."

The GOP in 2010 won the governor's office, which had been held by a Democrat, and the Senate seat that had been held by the late Arlen Specter, a Republican who became a Democrat toward the end of his career.

In 2012, a close Senate race, in which Republican Tom Smith has invested millions of his own money, has energized Republicans a bit about their prospects in Pennsylvania.

Winning in PA
Republicans have lost the last five presidential elections in Pennsylvania, largely because population shifts have increased the importance of suburban areas around Philadelphia.

The Keystone State's solid blue record in recent presidential elections belies its centrist electorate.

George W. Bush came within 3 percentage points of carrying the state in 2004, and Republicans claimed a Senate seat and the governor's mansion in 2010.

Obama won Pennsylvania by some 620,000 votes four years ago. But he won almost 600,000 of his votes in Philadelphia, the rambunctious, mostly non-white, overwhelmingly Democratic city that dominates the state’s south-east. Narrower victories in the Philadelphia suburbs, as well as in the western city of Pittsburgh and a small handful of blue-collar, union-heavy counties then carried him across the line.

In 2008, Obama won the four large suburban Philadelphia counties - Montgomery, Delaware, Chester and Bucks - by 200,000 votes, including an 80,000-vote margin in Montgomery. Combined with his 480,000-vote edge in Philadelphia, that made Obama unbeatable in the state.

Final election results in 2012 will probably turn on vital “collar” counties around Philadelphia. These suburbs have drifted from solidly Republican to undecided in recent years. In part, that is thanks to liberals fleeing the big city in search of better schools and greenery. In part, there is a growing gulf between a rock-ribbed state Republican Party and middle-class suburban Republicans who may be fiscally conservative, but are socially moderate.

Between blacks (and college students) in Philadelphia and Pittsburgh on the one hand, and the culturally conservative voters in central Pennsylvania on the other, a lot of the votes in Pennsylvania are preordained. There are certainly some swing voters in the Philadelphia and Pittsburgh suburbs, but in general the demographics of the state make turnout there a bit more important than persuasion.

To win, Obama will need another whopping turnout among core supporters to counter Republican strength in the “T”, a tree-shaped zone with a trunk and canopy of white, rural districts whose fierce views on guns, God and government are reminiscent of regions farther south (earning it the nickname “Pennsyltucky”). In the state’s south- western corner, the picture is completed by blue-collar, increasingly conservative communities built on such gritty industries as coal and steel.

Yet Mitt Romney has given the state only fitful attention.

If the GOP was to win in Pennsylvania, its path to victory would look something like this: Perform well with independent voters in the Montgomery County suburb of Philadelphia, win the surrounding exurban counties, hold Philadelphia to a 400,000-vote loss and win the suburbs around Pittsburgh.

Pennsylvania is well-known as a state with a large number of working-class whites, particularly in northeastern (Scranton, Wilkes- Barre and Hazleton, for example) and western Pennsylvania (Erie, Johnstown and Pittsburgh).Candidate Obama had problems with those kinds of voters in 2008.

Pennsylvania is home to an older population. Only Florida, West Virginia and Maine have a higher percentage of residents 65 years old or older, according to 2010 census data. And the Keystone State is white. Among the nation's dozen largest states, it ranks behind only Ohio for the lowest percentage of minority residents. Just more than one-fifth of Pennsylvania's population is minority, slightly above Ohio's 18.9 percent.