Hard-core supporters often see such appeals as a call to arms and a reason to pull out the checkbook. And most campaigns figure that as long as their candidate is under fire, they might as well try to derive some benefit from it.  Mr. McCain’s attack on CNN also serves to keep the episode involving the hostile question alive and as a reminder that many voters view Mrs. Clinton as divisive. Mr. McCain used the moment to portray himself as the victim of liberal news media — a common fund-raising tactic by Republicans — and to suggest that he can go toe to toe with Mrs. Clinton.  Rudolph W. Giuliani, the former New York mayor who is leading in the Republican polls, repeatedly says he has the best chance of beating Mrs. Clinton. This gave Mr. McCain all the more reason to issue a news release on Thursday highlighting a new Fox News poll that suggests Mr. McCain would do better than Mr. Giuliani against Mrs. Clinton. The numbers, though, were statistically insignificant and did not show that either he or Mr. Giuliani would actually beat her.  The Clinton campaign has not responded to the slur, which occurred in Hilton Head, S.C., at a McCain campaign event. But Clinton allies have suggested in the past that sexism-based attacks can actually help Mrs. Clinton by inspiring sympathy among women. They may even win over some voters who understand that campaigns are brutal but who appreciate a candidate who can “handle it,” as former President Bill Clinton recently said of his wife.  At the same time, the episode may remind voters that many people have strong feelings about Mrs. Clinton and make them question whether they want to live with animosity and polarization.  A version of this article appears in print on , on Page A30 of the New York edition with the headline: A Campaign Hopes a Slur Will Lead To Donations. Order Reprints| Today's Paper|Subscribe
John McCain sent out a fund-raising appeal based on an episode in which a voter referred to Hillary Rodham Clinton using a slur.