Democratic strategist James Carville once famously described Pennsylvania as "Philadelphia and Pittsburgh with Alabama in between."
As the fight for November comes in to focus, the Keystone State's 21 electoral votes will be key as the '08 race pits red against blue and moderate against moderate in Pennsylvania, a state that has gone Democratic in the last four presidential elections, though by ever-shrinking margins.
Sen. John McCain set sights on Pennsylvania as one of his top three Blue State targets in November; Democratic nominee Sen. Barack Obama lost the primary battle there to Sen. Hillary Clinton who was boosted to a 10-point lead by working-class white voters during the April primary.
McCain's hurdles include increased numbers of registered Democrats at the polls - a lead over Republicans that set state records by growing to 1.1 million following the primary. Obama faces an uphill battle where working-class whites and former Clinton supporters are concerned; the Illinois senator made conscious choices in Scranton son Sen. Joe Biden, D-Del., as his running mate and Pennsylvania Senator Bob Casey who (opposes abortion rights and) was given a prominent speaking role at the party's convention.
During an editorial board meeting with the Pittsburgh Post-Gazette in February, Pennsylvania Gov. Ed Rendell, who stumped for Clinton during the primary season, said some whites in his state are "probably not ready to vote for an African-American candidate."
The Philadelphia suburbs will be the keystone within the keystone come November -- McCain's maverick brand is said to resonate strongly with moderates there, a pocket of Pennsylvania where Clinton enjoyed strong support among women voters.
Check back to see when ABC News is headed to this battleground state and if -- and how! -- the political tide turns for either candidate.