The decision by labor leader Bill George, a Pennsylvania superdelegate, to fall off the fence and into New York Sen. Hillary Rodham Clinton's camp yesterday leaves five of the state's 30 Democratic superdelegates still undecided -- all of them congressmen, two of them from Western Pennsylvania.

And officially, at least, they're under no pressure to reveal their preferences before the primary season ends.

Mr. George, president of the Pennsylvania AFL-CIO, announced that he was supporting Mrs. Clinton's presidential candidacy because she "was the best equipped to beat Sen. John McCain in a general election," referring to the presumptive Republican nominee.

Nationwide, Mrs. Clinton leads her opponent, Illinois Sen. Barack Obama, in the superdelegate race, 263 to 243, The Associated Press reported. The superdelegates are especially valuable in this race because neither Mrs. Clinton nor Mr. Obama will be able to win enough delegates through primaries and caucuses to secure the nomination.

Mr. Obama has cut Mrs. Clinton's superdelegate lead in half in less than two months, and this week has picked up seven delegates to her four.

In the delegate count overall, Mr. Obama leads with 1,731.5 delegates to 1,597.5 for Mrs. Clinton, according to the AP's tally. A candidate needs 2,025 delegates to win the nomination. About 230 superdelegates remain undecided, and about 60 more -- three in Pennsylvania -- will be selected at state party conventions and meetings throughout the spring.

In an interview from his Harrisburg office, Mr. George stressed that he was acting as a member of the Democratic National Committee and a superdelegate, not as president of the state or national AFL-CIO, which have yet to make endorsements.

He said he decided to support Mrs. Clinton, who won the April 22 primary by a margin of 9.3 percent, after seeing polling that showed her margin of victory to be even wider among working families. He also cited her performance at an April 11 trade forum Downtown, where the New York senator showed "in-depth" knowledge of labor issues.

"At that particular meeting she was obviously much more well-read on trade policy and legalities," Mr. George said. Mrs. Clinton "has a strong record of joining workers in trade fights" before the World Trade Organization and other groups, he added.

While Mrs. Clinton still faces an uphill battle for the nomination, current polls show a tight race between the two candidates in Indiana, while Mr. Obama is ahead in North Carolina. Those states hold their primaries Tuesday.

"There's no question there's a challenge there, but because of her courage, persistence and tenacity, I felt there's a need to be supportive of her now," Mr. George said, adding that if Mr. Obama wins the nomination, "I'm going to support him 100 percent."

Indeed, "if he'd won the state, I'd probably have come out for him," he said.

The national AFL-CIO's board, representing 56 unions, will not make an endorsement until one candidate earns at least two-thirds support from the board's members, he said. To date, 13 member unions have endorsed Mrs. Clinton, while six have endorsed Mr. Obama.

The diverse makeup of the labor organization has made it difficult to reach a consensus, he said, noting that in Pennsylvania, 40 percent of the AFL-CIO's members are women, 17 percent are African-American and 4.5 percent are Latino.

"[AFL-CIO President] John Sweeney takes the pulse of the board every week with a conference call to see where people are at," but so far there's been no significant movement toward either candidate, Mr. George said. "It's actually a blessing. It shows we're a real democracy."

Rep. Mike Doyle, D-Forest Hills, one of the five remaining uncommitted congressional superdelegates in the state, said he thought it unlikely that any other Pennsylvania superdelegates would jump to either candidate before the primary season ends June 3.

While he received friendly "just checking in" phone calls from Mr. Obama on Friday and Mrs. Clinton on Tuesday, "I don't think there's pressure on anyone. Everyone knows what they're going to do. It's just a question of timing," Mr. Doyle said.

While state numbers still haven't been finalized, unofficial tallies show that Mr. Obama won Mr. Doyle's district -- which includes Pittsburgh -- 52 percent to 48 percent. Mrs. Clinton won the 17th District of Rep. Tim Holden, D-Schuylkill, which includes Harrisburg, by roughly 54 percent to 46 percent.

Three of the five remaining uncommitted congressional superdelegates represent districts that voted overwhelmingly for either Mrs. Clinton or Mr. Obama, prompting some party insiders to wonder what's taking them so long to decide.

In the 14th District, represented by freshman Rep. Jason Altmire of McCandless and which includes Pittsburgh's northern suburbs, Mrs. Clinton won by a 66 percent-to-34 percent margin. In the 10th District of Rep. Chris Carney of Susquehanna County -- also a freshman congressman whose territory includes much of northeastern Pennsylvania -- she won by 66 percent to 34 percent. In Philadelphia's 2nd District, represented by the powerful Philadelphia Democratic Party chairman, Rep. Bob Brady, Mr. Obama won 67 percent to 33 percent.

"While I can understand at this point they might as well wait until it's all over, hoping the decision will become obvious, if I were a freshman congressman, I would think I've got a decision to make. But I'm not going to tell them what to do. I don't think they need the aggravation," said Marcel Groen, a superdelegate who supports Mrs. Clinton and heads the Democratic Party in Montgomery County.

T.J. Rooney, who chairs the state Democratic Party and is a supporter of Mrs. Clinton, disagreed.

"I don't think vote margins should put any additional pressure on undecided superdelegates," Mr. Rooney said. "I respect the fact that they're taking the time. It's a personal decision, and they must make it on their terms and follow their conscience, not any prescribed margin of victory."

Indeed, Mr. Doyle noted, there is nothing in party rules that says a superdelegate must follow the wishes of the electorate.

"They're all over the place at this point," he said. "Look at Massachusetts, which voted overwhelmingly for [Mrs.] Clinton, but Sens. [Edward M.] Kennedy and [John F.] Kerry are for Obama. Of course, if my district has an overwhelming response to one candidate, that would be a heavier factor for me. Smart elected officials need to be sensitive to what's on the minds of their constituents, which is why my district's vote will be a determining factor but never the sole factor,"