From the WallStreet Journal [HERE]
By JUNE KRONHOLZ 

Hillary Clinton's advantage going into Tuesday's Pennsylvania primary was that she could win the most votes in the state. Barack Obama's advantage was that he could win the most votes in some of the right places.

Pennsylvania's 187 convention delegates are the largest remaining lode in the primary season, dwarfing the 134 delegates in North Carolina and 83 in Indiana, states that vote in two weeks. But the party's process of choosing delegates means Tuesday's vote wasn't likely to resolve the nomination.

Pennsylvania may "have tremendous public-relations impact, but a minimal practical impact," said University of Virginia political scientist Larry Sabato.

Under party rules, congressional districts that voted most heavily Democratic in recent general elections get more delegates to the party's national convention in Denver in August. In Pennsylvania, districts that went most heavily for Democrats in the 2004 presidential and 2006 gubernatorial races got the most seats.

All states use a similar formula, which dates to the 1970s and was intended to reward constituencies and voters most loyal to the party, said Democratic strategist Tad Devine. But the effect is most pronounced in states with large and concentrated African-American populations, which tend to be most loyal to the party.

That increases the clout of those minorities, which has benefited Sen. Obama. In Texas, African-American votes for Sen. Obama in delegate-rich Houston and Dallas largely offset Hispanic votes for Sen. Clinton in the delegate-poor Rio Grande Valley. Sen. Clinton netted just four more delegates in the primary than Sen. Obama did, despite winning the popular vote by 101,000 votes and 3.5 percentage points.

Pennsylvania posed a similar opportunity. Philadelphia's 2nd Congressional District, where Sen. Obama long has had his strongest support, will send nine people to the national convention. Two nearby districts with similarly large African-American populations will send seven delegates each.

Sen. Clinton's strength has long been in the state's northeastern and southwestern counties, where many districts have only four delegates. To win three of those four delegates, a candidate would have to win a whopping 60% of the district's popular vote.

That means that big wins in Philadelphia and in Pittsburgh, which also has a sizable minority population, can partly offset more-numerous victories in the state's other districts. Before the Pennsylvania vote was tallied, Sen. Obama led Sen. Clinton by 1,648 delegate votes to 1,509, according to a Wall Street Journal calculation, with 2,025 needed to secure the nomination.

There is little chance of either candidate significantly widening or narrowing that delegate gap in the remaining nine contests. Most polls show Sen. Obama with a wide lead over Sen. Clinton in North Carolina and a slim lead in Indiana. But the Democrats' proportional-representation system means that the rivals will share the delegates fairly evenly, unless one candidate manages a runaway win.

Sen. Clinton's advantage in Pennsylvania is among the at-large delegates, who accounted for 55 of the 158 delegate seats at stake Tuesday. Those delegates are awarded according to each candidate's share of the statewide popular vote. But even that isn't likely to make a significant difference: A six-percentage-point win, for example, would translate into just three additional at-large delegates.

Sen. Obama has the same limited advantage in North Carolina, where the popular vote could net him a few more at-large delegates, but not enough to pull away.

The biggest impact of a popular-vote victory in Pennsylvania could be the effect it has on the remaining unpledged superdelegates, who are party leaders and elected officials. Pennsylvania has 29 superdelegates, 14 of whom already have endorsed Sen. Clinton, and seven who have endorsed Sen. Obama, according to a Wall Street Journal analysis.

Sen. Clinton also leads in superdelegates nationally, with 258 to Sen. Obama's 233. Some 304 superdelegates remain uncommitted, and Democratic Chairman Howard Dean is pressing superdelegates to make a decision and settle the nomination by July.

The Clinton campaign counted on a big victory in Pennsylvania, a perennial battleground state, getting those superdelegates off the fence by convincing them of her electability. Similarly, the Obama campaign hoped that a modest popular-vote victory for Sen. Clinton would create doubt among the superdelegates and create a drift to him.