Sen. Arlen Specter has learned a tough show-biz lesson: What plays well in Philly could bomb in New York.

Before hundreds of Pennsylvania Republicans in Manhattan last weekend, Specter told a couple of Polish jokes.

Not only did they bomb, but also someone tipped off a New York Post reporter, who wrote a brief account.

Now the chagrined senator is apologizing to Polish leaders around the country.

"It was insensitive and inappropriate," Specter said yesterday. "I have a pretty good reputation on ethnic issues and civil rights. This was a mistake."

He said that during a tribute to late Philadelphia GOP leader Billy Meehan a couple of weeks earlier, the stories about Meehan were flowing.

"One of the things he was noted for was his storytelling - Polish stories, Irish stories, Jewish stories, all kinds," Specter said. "To reminisce, I told some of the stories, including two Polish stories."

He repeated the stories at a luncheon during the annual Pennsylvania Society Weekend in New York, he said. According to the New York Post, when Specter asked if anyone in the audience was Polish, about 10 people raised their hands. He then told the jokes.

Since then, Specter has spoken with, among others, Michael Blichasz, president of the Polish American Congress of the Eastern District of Pennsylvania; Tim Kuzma, president and chief executive officer of the Polish Falcons of America; Rick Pierchalski, president of the Polish Cultural Council of Western Pennsylvania; and Frank Spula, president of the Polish American Congress in Chicago.

"All I could do was admit I was wrong and apologize," Specter said.

He said the Polish leaders from Pittsburgh would visit Washington in January to talk to him about several issues.

Blichasz said he had forwarded Specter's letter of apology to his 7,500-name e-mail list and received thousands of responses.

"He has been a longtime friend of the Polish community," Blichasz said. "That's why this is a tragedy, but he did apologize with the right words: It was inappropriate, and it will not happen again."

Still, he said, many of his members were angry and wanted to hear Specter apologize personally.

Specter launched a career in stand-up comedy about a year ago when he appeared at a Washington improv club. He told off-color jokes about Bob and Elizabeth Dole and Viagra. He told an irreverent joke about Sens. Joseph R. Biden Jr., Barack Obama, and Hillary Rodham Clinton. He made fun of former Sen. Trent Lott and his two-volume library.

But he broke the crowd up with a joke about the Americans With Disabilities Act, including a punch line too raunchy for a family newspaper. Specter said yesterday that it was an adult crowd that expected to hear jokes that were a little blue.

"Some of those stories are a little rough, but when they put it on YouTube, I got a little queasy," he said.

"There is an old adage: Live and learn. And I'm doing a lot of learning."