Politics

PHILADELPHIA (CBS) ― After weeks of campaigning, the spotlight is now on voters as polling places across the state of Pennsylvania are now open for primary day.

On the top of the ticket is the contentious presidential primary race between Democratic Senators Barack Obama and Hillary Clinton. With an extremely close race between the two, Pennsylvania's 158 delegates could prove to have a major impact for the first time in nearly 30 years.

Both Clinton and Obama have spent the day greeting voters. At a morning news conference, Clinton touted her expected victoy in the Keystone state.

"A win is a win," she said.

Clinton also took the opportunity to raise questions about Obama's electability. After pointing out that he has outspent her and raised more money than her, Clinton said "Maybe the question ought to be 'why can't he close the deal?'"

Clinton was pointing to her victories over Obama in larger, delegate-rich states. Obama has won more smaller states than Clinton.

Voter registration jumped in anticipation for the primary, with an increase of nearly 317,000 Democrats. Obama told CBS station KYW-TV in Philadelphia he believes the close race could lead to a record number of voters at the polls.

Clinton and Obama questioned each other's character and readiness to be commander in chief in last-minute television ads as the six-week Pennsylvania primary campaign steamed toward an uncertain conclusion.

The two Democratic hopefuls barnstormed the state in a final pitch for votes in the most populous and delegate-rich state remaining in the nominating contest. Some 4 million Democrats were eligible to cast ballots.

Clinton was relying on a decisive win to save her flagging candidacy, while Obama hoped for an upset or a strong enough finish to secure the delegates needed to maintain his overall lead.

Late polling showed Clinton with a single-digit lead in the state, after besting Obama by 20 points or more in earlier surveys.

Supporters for both candidates have been out in force throughout the state, but the decision will ultimately fall on those who vote. Philadelphia District Attorney Lynne Abraham said there will be precautions in place to help avoid any major problems.

"When a lot of people are out there for a side, there's always a potential for a lot of pushing and shoving and jawboning" she said.

The Justice Department is also going to great lengths to ensure a fair primary day. Federal observers will be out in force around Philadelphia to make sure polling locations are compliant.

Clinton was relying on a decisive win to reinvigorate her candidacy, while Obama hoped for an upset or a strong enough finish to secure the delegates needed to maintain his overall lead.

Late polling showed Clinton with a single-digit lead in the state after besting Obama by 20 points or more in earlier surveys.

As the polls opened at 7 a.m., the candidates engaged in a last round of sparring in pre-taped interviews aired on network and cable television.

"What (Obama) has to demonstrate is to win a big state, a big state that Democrats need to win in order to achieve the presidency," Clinton told CBS' "The Early Show." "The road to Pennsylvania Avenue for a Democrat goes right through Pennsylvania."

Obama, noting Clinton's polling lead, sought to lower expectations both in TV interviews and as he greeted the breakfast crowd at a Pittsburgh diner.

"We think we've made enormous progress" though "it's an uphill battle," Obama said. He noted that polls show a tighter race than just a few weeks ago but said: "We still, I think, have to consider ourselves the underdog."

"We've got a great organization. A lot of it's going to depended on turnout," Obama added.

Sarah Triplett arrived to vote Tuesday long before her suburban Philadelphia polling place opened and soon had plenty of company.

"I had to be here to vote, and I pray that Obama does make a big change in a very positive way," said Triplett, a "65-plus" woman from Levittown who works with the disabled.

In Allentown, where a line snaked out the door at First Presbyterian Church, 68-year-old Ellen Woolley, who works in finance, went for Clinton. Obama, she said, is a "marvelous speaker, but I really don't hear a lot of substance."

The issue of race in the campaign was renewed when former President Clinton, asked in an interview broadcast Tuesday with Philadelphia radio station WHYY about comments he made before the South Carolina primary, said the Obama campaign "played the race card on me."

"And we now know, from memos from the campaign and everything, that they planned to do it all along," Bill Clinton said.

Asked about Clinton's remarks, Obama chuckled and said: "So, former President Clinton dismissed my victory in South Carolina as being similiar to Jesse Jackson, and he's suggesting that somehow I had something to do with it? Ok, well, you'd better ask him what he meant by that. I have no idea what he meant. These were words that came out of his mouth, not words that came out of mine."

Obama and his wife, Michelle, addressed a rally at the University Pittsburgh on Monday night. They were joined by Teresa Heinz Kerry, wife of 2004 Democratic nominee John Kerry.

Heinz Kerry noted that her husband carried Pennsylvania in the general election. "I'm asking you to keep this streak going," she said.

In Philadelphia, Clinton appeared with her husband and their daughter, Chelsea, before a crowd at the University of Pennsylvania.

"It's not enough to say 'Yes we can.' We have to say how we can," Clinton told the crowd, putting a twist on Obama's popular slogan of hope.

The Pennsylvania contest turned sharply negative in its closing days as Obama cast doubts on his rival's honesty and trustworthiness. Clinton, in turn, questioned whether Obama was tough enough for the rigors of the Oval Office.

The campaigns tangled Monday over a new Clinton television ad that invoked images of Osama bin Laden - the first time a Democratic candidate has used the mastermind of the Sept. 11, 2001, terrorist attacks in the 2008 race for the White House.

"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 ad says, as a picture of bin Laden and other national emergencies - from Hurricane Katrina to the fall of the Berlin Wall - flash on the screen.

The Obama campaign moved quickly to counter the message, airing a response ad within hours that challenged Clinton's 2002 vote authorizing the U.S. invasion of Iraq.

Obama addressed the matter himself at the Pittsburgh rally.

"My job as commander in chief is to keep you safe. That will be my number one task," adding, "The war in Iraq was unwise."

Pennsylvania's demographics suit Clinton. The state has a higher median age, a higher percentage of whites, a lower median household income and fewer bachelor's degrees than the country overall. These are the voters - working-class whites and voters older than 50 - who have flocked to her in past contests.

The Republican primary is also being held Tuesday, but Sen. John McCain of Arizona is already the certain nominee.

(© 2009 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)