A new Web video from McCain's campaign casts Hayworth as a loony right-winger who suggests the president was born in Kenya and thinks gay marriage will lead to marriage between men and horses.

"I've committed to exposing the secret Kenyan brithplace of the president of the United States," the fake Hayworth says. "Second, I've stood up against the grave threat of man-horse marriage."

The video is a parody of a Hayworth ad, pretending to promote the candidate's positions on those issues. McCain has previously attacked the challenger for his comments suggesting Obama should prove his citizenship.