( dpa )- With Democratic presidential contenders Barack Obama and Hillary Clinton both already campaigning in Pennsylvania this week, one could be forgiven for thinking the state's contest was just around the corner.
But Pennsylvania, the largest state left in the tight party nomination battle, will not have its say until April 22 - a full six weeks from Tuesday's Mississippi primary.
Obama soundly defeated Clinton in Mississippi by 20 percentage points, but the Illinois senator had left the southern Gulf state long before the polls closed, making campaign stops in Pennsylvania before retreating to his home town of Chicago for a night of regrouping.
The 42-day gap between the Mississippi and Pennsylvania primaries is by far the longest since the string of state-by-state nominating contests began January 3 in the tiny Midwestern state of Iowa.
Most pundits - and no doubt a fair few in each campaign - thought it would all be over by February 5, when more than 20 states picked their preferred nominee.
Republican Senator John McCain was virtually assured of his party's nomination after Super Tuesday and last week ousted his only remaining rival Mike Huckabee, but for the Democrats it wasn't to be.
Now, with only eight of the 50 states left to vote, Obama and Clinton are separated by only about 130 of the more than 3,000 delegates that have been divided up so far. To win, one of them will need 2,025 delegates on their side at the party's August nominating convention in Denver, Colorado.
Obama, 46, has work to do if he hopes to pull off a Pennsylvania victory. Clinton, 60, who has family roots in the eastern state, leads by an average of 12 percentage points in recent opinion polls. The former first lady could well be forced out of the race if that advantage does not hold up come April 22.
Obama, who is vying to be the first African-American president, will have six weeks to make inroads into her significant Pennsylvania lead, and given how unpredictable and fluid the race has been to this point, pollsters say anything is possible.
"Everything I've seen so far this year suggests that Democrats are willing to change their mind," Frank Newport, Gallup Poll's editor in chief, told Deutsche Presse-Agentur dpa.
Newport said Clinton clearly has the edge over Obama in Pennsylvania, "but that doesn't mean that he can't come from behind."
Obama finds himself at much the same disadvantage in Pennsylvania as he did last week in neighbouring Ohio, a rust-belt state with a similar demographic of working class voters concerned about the faltering economy. Clinton took Ohio by 10 percentage points, a victory that along with Texas halted Obama's string of 11 straight contest victories in the month of February.
Pennsylvania is likely to see an unprecedented swirl of candidates, their surrogates and reporters descend on the eastern state in upcoming weeks, and it remains to be seen just what kind of campaign the two candidates plan to run.
Clinton, Obama and their supporters have launched into an increasingly negative and personal series of exchanges in the last few weeks - a sign of raw emotions in both camps that many Democrats fear could harm the party's chances of beating McCain in the general election on November 4.
Samantha Power, a Harvard University professor and top Obama advisor on foreign policy, was forced to resign from the campaign last week after calling Clinton "a monster" in an interview with The Scotsman newspaper.
Clinton herself has suggested Obama is unfit to be commander in chief, while former Democratic vice presidential candidate Geraldine Ferraro this week brought the charged issues of race and gender back into the equation.
Ferraro, a chief fundraiser and advisor to Clinton, told the Daily Breeze newspaper of Torrance, California, that "if Obama was a white man, he would not be in this position" of leading the nomination battle.
Obama told CNN after Tuesday's result that his campaign has tried to remain above the fray, and accused Clinton's aides of taking a more personal tone.
"We've been very measured in terms of how we talk about Senator Clinton," Obama said. "I'm not sure that we've been getting that same approach from the Clinton campaign."
In terms of campaigning style, the long and drawn out Democratic race will come full circle in Pennsylvania. The six-week lag allows the two sides to set up grassroots movements and spend the kind of time in one state that has not been seen since the initial stages.
"I think this long period of time just gives them the opportunity to really deploy people on the ground - kind of like Iowa," Gallup's Newport said.