Audio: Gerard Baker on how Philadelphia changes the race

The most overworked cinematic cliché employed during the Pennsylvania primary campaign was the Hillary-As-Rocky-Balboa meme. This modern Philadelphia story of resilience in the face of overwhelming odds was too good for most commentators to pass up, especially when Hillary Clinton likened herself to the Sylvester Stallone hero.

But as it turned out a rather better analogy for Pennsylvania from the movie library might be Groundhog Day.

You’ll recall that in the iconic 1993 film, Bill Murray plays a weatherman who is condemned to repeat, apparently forever, his tedious day in the cloyingly friendly Pennsylvanian town of Punxsatawney, where a groundhog named Phil pops his head out of a tree every year and determines how much more winter there will be.

Pennsylvania on Tuesday was yet another Groundhog Day for the Democrats. Almost every primary in the last few months has promised to produce a resolution to this titanic struggle. Surely one of the candidates (usually Barack Obama) would do enough finally to finish off the other?

But with every primary, we wake up the next morning, and sure enough, the race is back on, and we’ve got to keep running it, day after day.

Mrs Clinton won on Tuesday by just enough votes to keep the Democratic show on the road for at least the next two weeks, when the next primaries are held, and quite possibly, for all we know, into eternity.

Mrs Clinton was expected to win but her ten percentage point margin was somewhat better than the consensus of expectations, as measured at least by pre-election opinion polls.

Both campaigns had plenty of talking points to explain their performance. For Mr Obama it was that Pennsylvania was an inhospitable state, full of working-class white voters. He trailed by a wide margin just a couple of months ago. After his worst few weeks in the entire primary season – all those revelations about his friend the radical black pastor, Jeremiah Wright, and his observations about “bitter” voters “clinging” to religion and guns – he still performed well.

Mrs Clinton could point out that Mr Obama outspent her by millions of dollars in television advertising and still could not win. That he was unable to appeal to the kind of people who will be crucial swing voters in the November general election. Above all, she could make the point that, despite his leads in the primary campaign, he simply can’t close the deal.

For Mrs Clinton the victory had two particular benefits in the battle to win the hearts and minds of the “superdelegates “ who will determine the outcome of this nomination battle. Mr Obama, barring a collapse between now and the end of the primary process in June, cannot be beaten in the race for elected delegates – those chosen in rough proportion to votes cast in the primaries. But he cannot win enough of those to secure the majority a candidate needs to secure the party’s nomination. So the tussle comes down to persuading the superdelegates, the party’s panjandrums who now hold the balance of power.

Mrs Clinton’s efforts to persuade those superdelegates not to simply endorse the votes of the elected delegates is strengthened after Pennsylvania in two ways.

First, she can argue that Mr Obama is steadily demonstrating what the Clintons believe to be the essential truth about him – he cannot beat the Republican, John McCain, in November. His performance among white working class swing voters in Pennsylvania (as in Ohio) was simply not good enough to carry the Democrats to victory in November.

The second point she can make concerns the popular vote. Though it holds no official role in the election decision, the popular vote holds great moral authority. A number of superdelegates could well be persuaded to vote for the candidate who ends the primary season with more actual votes cast in all the primaries and caucuses.

Before Pennsylvania Mrs Clinton trailed Mr Obama in that tally by 700,000 votes. Her margin of victory on Tuesday was enough to close that gap by more than 200,000 votes. If you include the results from the Florida primary – whose voters are disenfranchised because the state opted to hold its primary before it was supposed to, Mrs Clinton, who won the state, would cut the popular vote deficit to 200,000.

There are nine states to come – beginning with North Carolina and Indiana on May 6, and it is just possible that Mrs Clinton could draw level with Mr Obama in the popular vote. If that happened, it would give her a powerful argument that she should be the nominee.

It’s still a long shot, however. The arithmetic still favours Mr Obama and the odds on a Clinton win are still long. But the Pennsylvania result has condemned Mr Obama to living through a few more Groundhog Days yet.

Times Recommends

• We need bankers more than they need us
• Rooms need a view. Hoteliers don’t
• Wootton Bassett, outpost of lost England