All eyes in the U.S. presidential election campaign are on Pennsylvania, where voters will cast ballots Tuesday in the race for the Democratic Party nomination. VOA's Paula Wolfson reports from southwestern Pennsylvania that Senators Barack Obama and Hillary Clinton are campaigning in the state almost non-stop.

Turn on just about any radio or television anywhere in Pennsylvania and this is what you are likely to hear:

Both Obama and Clinton are saturating the state with campaign ads. Governor Edward Rendell - a former mayor of Philadelphia - says he has never seen anything like it.

Rendell, a top Clinton supporter, appeared on the CBS network news program Face the Nation. He says Obama is outspending Clinton in Pennsylvania by a margin of more than three to one.

"I have always been a good money raiser and I have put a lot of money on TV in the closing weeks of my campaign," said Governor Rendell. "But I never exceeded $1.2 or $1.3 [million]. The Obama campaign: $2.9 million. You cannot go anywhere in the Philadelphia region, you cannot listen to TV for 10 minutes without seeing an ad!"

The ad campaign has helped Obama cut Clinton's lead in the state from double digits to about five or six percent. Senator Robert Casey - considered the most popular Democratic Party office holder in the state and an Obama backer - says he will not predict what will happen when voters go to the polls on Tuesday.

He also appeared on Face the Nation.

"I think it is going to be an interesting night on the 22nd," said Senator Casey. "I do not think anyone knows where it will end. But I do think that from Senator Obama's perspective that he has made tremendous progress in the last six or seven weeks."

Both Rendell and Casey have put their prestige on the line in this election. Casey has been traveling across the state with Obama in the final days of the primary campaign, traveling by train from one town in eastern Pennsylvania to another.

At all stops, Obama has been focusing on his message of change.

"The choice you have right now in this Pennsylvania primary is whether to vote your hopes or your fears, whether you decide to not accept what the cynics tell you you have to settle for, but instead you decide to reach for what is possible," said Barack Obama.

Pennsylvania has the second oldest population in the nation, right behind Florida. And while the Obama campaign's focus on change has resonated with young voters, it has fallen flat with many of their grandparents.

Seniors remain a strong voting bloc in the state, and they are more attracted to experience and stability. At her campaign stops in the Pittsburgh area, Clinton is telling voters that they have to fill the most important job in the country, and experience counts.

"Who would you hire to restore our reputation and leadership in the world," asked Hillary Clinton. "And who would you hire to end the war in Iraq and win the war in Afghanistan?"

Pennsylvania voters originally thought their primary might be an afterthought in the campaign. It is one of the last of the big populous states to vote in the selection process, coming months after the February primaries that, at one point, were expected to decide the Democratic nominee.

Now Pennsylvanians find they are at the center of a protracted fight for the party nomination. And there are signs this state will also be a big battle ground months from now in the general election campaign. Not only are Barack Obama and Hillary Clinton running ads here, but so too is the presumptive Republican nominee, Senator John McCain.