That’s no accident. Not only is Pennsylvania a key state in the election, it’s also full of the blue-collar voters who may well prove to be the swing voters in the swing states this year.

Many of them are in the 900,000-member Pennsylvania AFL-CIO, which is the fourth-largest state labor federation after New York, California and Illinois. Its president, Bill George, is among the country’s most-respected labor leaders. He’s also a member of Pennsylvania’s delegation at the convention in Denver.

Barack Obama will be hard pressed to win Pennsylvania, or the election, without securing this voting bloc, including the blue-collar conservatives/Reagan Democrats John McCain also is wooing.

In a telephone interview Wednesday from a noisy event at which Clinton delegates were being released, George was optimistic. The convention really got going Tuesday night, he said, with all the speakers focusing on the kind of economic message he says the election is really about, including what the current administration has done to the status of ordinary Americans.

In addition, George said, Joe Biden, the senator from neighboring Delaware, but a native of Pennsylvania, will be a big help as Obama’s running mate.

“We call him Pennsylvania’s third senator,” George said. Beyond geography, Biden’s working-class appeal is expected to help among the union members and blue-collar workers George represents — and Obama needs.