State GOP officials disavowed the e-mail and said the strategist who helped draft it had been fired.
"The Republican Party of Pennsylvania did not authorize that e-mail," Michael Barley, communications director for the state Republican Party, told The Associated Press on Saturday evening. Barley said a "correction" would be sent out to everyone who received it.
McCain-Palin spokesman Peter Feldman said Saturday night that McCain "rejects politics that degrade our civics."
"Throughout his life John McCain has held himself to the highest standards and he will continue to run a respectful campaign based on the issues," he said.
Barley declined further comment, but referred the AP to his comments to The New York Times, in which he apologized and said political consultant Bryan Rudnick helped draft it and had been fired for that and other reasons.
Rudnick, reached Saturday night, confirmed that he no longer works for the party, which employed him a few weeks ago as a consultant to do outreach to Jewish voters.
"I had authorization from party officials" to send the e-mail, Rudnick said, but he declined to say who had signed off on it. "I'm not looking to drag anyone else through the mud, so I'm not naming names right now," he said.
The e-mail was sent Thursday morning to 75,000 Jewish voters, and Rudnick said he was fired the following morning. "I was informed that it mostly had to do with discrepancies with strategy and logistics, and the e-mail was not mentioned," he said.
A copy of the e-mail provided by Democratic officials says it was "Paid for by the Republican Federal Committee of PA - Victory 2008." It warns "Fellow Jewish Voters" of the danger of a second Holocaust due to the threats to Israel from its neighbors and touts McCain's qualifications over those of Obama.
"Jewish Americans cannot afford to make the wrong decision on Tuesday, November 4th, 2008," it says. "Many of our ancestors ignored the warning signs in the 1930s and 1940s and made a tragic mistake. Let's not make a similar one this year!"
The e-mail accuses of Obama, in his role as a community activist, of teaching members of the community group ACORN "to commit voter registration fraud."
The grass roots community group Association of Community Organizations for Reform Now has been the target of voter fraud allegations and lawsuits in a number of states. But Barley told The New York Times that there was no substantiation for the claim and the party should not have made it.
The e-mail also accuses Obama of having associated with "a known terrorist, William Ayers, who thought the terrorists didn't do enough on 9/11." Ayers was a former member of the radical 1960s Weather Underground group, and was quoted in an interview as saying that group - not the 9/11 terrorists - "didn't do enough" to stop the Vietnam war.
The e-mail was signed by former state Supreme Court justice Sandra Schultz Newman, a member of McCain's task force monitoring election day voting; real estate developer Mitchell L. Morgan, who has raised funds for McCain; and steel industry executive I. Michael Coslov. Coslov and Morgan have unlisted numbers and a listed number for Newman could not be found; messages left at the offices of Newman and Morgan and with a spokesman for Coslov's firm were not immediately returned.
Rudnick, president of Alliance Strategies Group of Boca Raton, Fla., said that other than the 9/11 reference, he stood by the contents of the e-mail, including the reference to voter fraud. "We made that remark based on information found all over the Internet," he said.
Casey called Rudnick's firing "a good development" but called on the GOP to focus on issues rather than attacks on Obama, citing comments like GOP vice presidential nominee Sarah Palin's accusing Obama of "palling around with terrorists" because of his contact with Ayers.
"I said earlier the day I must have missed the sale on kitchen sinks, because this isn't just 'throw the kitchen sink' at your opponent - they're throwing every kitchen sink they can get their hands on, and some of it's just fabrication," Casey said.