The New York senator needs a big win today to keep her hopes alive, writes Denis Stauntonin Philadelphia.
AFTER THE most aggressive week of campaigning so far in the Democratic presidential race, Barack Obama adopted a gentler approach when he came to the Philadelphia suburbs yesterday, posing before a tableau of tulips, daffodils and frolicking children.
"I thought this would be a nice change of pace," he said before pleading for votes ahead of today's Pennsylvania primary.
If the tone of campaigning has been sharper in recent days, it is because today's contest is a key test for both candidates that could settle the Democratic nomination altogether.
Hillary Clinton needs a substantial victory to keep alive her dwindling hopes of clinching the nomination and a loss in Pennsylvania would most probably end her candidacy immediately.
"We really need to bear down in these last few days. The whole world is watching," the former first lady told supporters yesterday in her father's home town of Scranton.
Mrs Clinton yesterday became the first Democratic candidate to use Osama bin Laden in a campaign ad, flashing a picture of the al-Qaeda leader along with images from the stock market crash, the bombing at Pearl Harbor, the fall of the Berlin Wall and Hurricane Katrina as an announcer says the presidential race is about filling the most important job in the world.
"You need to be ready for anything, especially now, with two wars, oil prices skyrocketing and an economy in crisis. Harry Truman said it best, 'If you can't stand the heat, get out of the kitchen'. Who do you think has what it takes?" the voiceover says as Mrs Clinton appears on screen.
Mr Obama's campaign accused Mrs Clinton of playing "the politics of fear", adding that bin Laden would probably have been captured by now if she had not voted to authorise the Iraq war.
"It's ironic that she would borrow the president's tactics in her own campaign and invoke bin Laden to score political points," spokesman Bill Burton said.
Mr Obama has been playing a little rough too, however, running negative ads across Pennsylvania that Mrs Clinton claims are misleading voters about her healthcare plan. Mr Obama said yesterday that he expects Mrs Clinton to win today's primary but he hopes to keep her margin of victory as narrow as possible.
"I'm not predicting a win," he told Pittsburgh radio station KDKA. "I'm predicting it's going to be close and that we are going to do a lot better than people expect." A big win for Mrs Clinton would not only keep her in the race but could also reinforce doubts about Mr Obama's chances of winning the big, industrial battleground states in a general election. Polls show Mrs Clinton faring better in key swing states like Pennsylvania, Ohio, Michigan and Florida, partly because of Mr Obama's weakness among the older, white, working-class voters that make up such a large part of Pennsylvania's electorate.
Mr Obama should win Philadelphia, where almost half the population is African-American, and he hopes to fare well in the city's affluent suburbs. Mrs Clinton is ahead everywhere else in the state, however, and both campaigns have moved thousands of paid staff and volunteers into the state to boost turnout.
Most polls give Mrs Clinton an edge of about 6 per cent but there are two unpredictable factors that could determine the outcome - undecided voters and newly registered Democrats. About 9 per cent of voters are still undecided and pollsters believe that most of those will back Mrs Clinton. A similar number, however, are newly registered Democrats, two out of three of whom say they favour Mr Obama.
A double-digit victory would give Mrs Clinton the boost she needs to fight on in North Carolina and Indiana on May 6th and perhaps to the remaining contests before early June. A narrow win may not be enough to keep her campaign alive, however, not least because she has run out of money.
Filings released yesterday showed that Mr Obama started April with $41 million cash in hand and about $650,000 in debts, while Mrs Clinton had just $9 million cash in hand and $10 million in debts.
Most of Mrs Clinton's reliable donors have already contributed the maximum allowed by law but Mr Obama's donors, who give an average of less than $100, can continue to contribute.
Even a blow-out victory in Pennsylvania would not bring Mrs Clinton close to overtaking Mr Obama among pledged delegates or in the accumulated popular vote, where he has a 700,000 lead. Her best hope lies in the political impact of a big win on super-delegates, the party figures whose votes are likely to determine the outcome of a close contest.
If Mrs Clinton wins big in Pennsylvania, some superdelegates may pause before endorsing Mr Obama, fearing that his nomination could be a recipe for the Democrats's third presidential election defeat in a row.