DENVER -- Sen. Joe Biden, who has often referred to himself as Pennsylvania's third senator, claimed the mantle again in a surprise visit to the Pennsylvania delegation breakfast this morning.

The Delaware senator, looking just a little bleary eyed after his big night, spoke to the delegates then worked his way slowly out of the banquet room, shaking hands and posing for pictures for a full half-hour before finally getting on the road.

But Mr. Biden assured the delegates it wouldn't be their last glimpse of him.

Touting his native state as a central battleground of the election, he told them the Obama campaign planned to devote abundant resources, staff and money to the state.

"That's the good news," he told the Pennsylvania politicians. "The bad news is you're going to see a whole hell of a lot of me because I'm coming home."

He'll take the first step in redeeming that promise tomorrow, when he and Mr. Obama open their post-convention swing with a rally in Beaver.

"It is not hyperbole -- we cannot win without winning Pennsylvania. It is that simple," he said.

Mr. Biden mixed nostalgia with practical politics as he repeatedly invoked in his Scranton roots as an abiding influence in his political career.

"There's a lot of people I should recognize because as they say, you brung me up," said Mr. Biden, speaking to about 400 delegates and his wife, Jill. "Scranton never leaves you. Pennsylvania never leaves you."

Mr. Biden traced his political awakening to the Sunday mornings of his youth, listening to the men in his extended family as they sat around the kitchen table. He recalled that when he first ran for the Senate in Delaware, at the age of 29, busloads of Scranton residents showed up at the Wilmington train station to cheer him on.

That anecdote reminded him of one of the early disadvantages of being Mr. Obama's running mate.

"If I hear one more time he was 11 years old when I went to the Senate, I'm going to smack somebody," Mr. Biden said.

Baiting the loquacious senator, the GOP has started a Web site counting down the time before he makes the first "gaffe" of the new campaign.

But Mr. Biden was on his best behavior today as he worked the crowd tirelessly on his way out of the room.

He smiled through hugs, handshakes and misfiring cameras as the Pennsylvania delegates formed a dense crowd around him and his new Secret Service escorts.

As she watched him leave, state Rep. Chelsa Wagner, D-Brookline, predicted he would be an asset to the ticket in places like her South Hills district, where Mr. Obama trailed in the Pennsylvania primary.

"For my district, it will help to have someone who's known, that will help, she said. "In the primary Hillary was so much better known but I think an Obama-Biden ticket will make a difference in Pittsburgh."

One of the many Pennsylvanians he paused to chat with was Allegheny County Chief Executive Dan Onorato.

Mr. Onorato said that the senator showed his knowledge of southwestern Pennsylvania politics, adding that the ticket's margin in the region would be a key to winning the state.