Obama is a member of the United Church of Christ.
A hoax e-mail that has been widely circulated suggests Obama is some sort of Manchurian candidate for Muslims.
Judy Rose, a Clinton coordinator in Jones County, Iowa, forwarded it without comment to eight people on Nov. 21, according to a copy of the e-mail obtained by The Associated Press. One of the recipients was a Clinton staffer and another was Gary Hart, a Democratic Party official in Jones County.
Hart is a supporter of Connecticut Sen.and posted an item about the "hateful" e-mail on the liberal blog Daily Kos. The Clinton campaign responded by asking Rose to step down.
"There is no place in our campaign, or any campaign, for this kind of politics," Clinton campaign manager Patti Solis Doyle said in a statement Wednesday. "A volunteer county coordinator made the mistake of forwarding an outrageous and offensive chain e-mail. This was wholly unauthorized and we were totally unaware of it."
According to a release on the Clinton campaign Web site, Rose is from Anamosa, Iowa, and served on Clinton's Women's Leadership Council. Rose did not respond to an e-mail requesting comment.
The Obama campaign declined to comment on her resignation.
The e-mail that Rose forwarded points out that Obama's father and stepfather were Muslim and that Obama lived in Indonesia for part of his childhood. But other parts of the e-mail are false - Obama attended public and Catholic schools in Indonesia, not a radical Islamic school. It is also not true that Obama used the Koran instead of the Bible when sworn into office or that he ever "admitted" to being a Muslim.