The Republican Party will begin airing a hard-hitting ad this weekend that warns of more cataclysmic terror attacks against the U.S. homeland. The ad portrays Osama bin Laden and quotes his threats against America dating to February 1998. These are the stakes," the ad concludes. "Vote November 7." The ad displays an array of quotes from bin Laden and his top lieutenant, Ayman al-Zawahri, that include bin Laden's Dec. 26, 2001 vow that "what is yet to come will be even greater." The ad also cites al-Zawahri's claim to have obtained "some suitcase bombs," followed by a scene that appears to show a nuclear explosion. Despite al-Zawahri's claim, portable nuclear devices are believed to be particularly difficult to produce and elusive to rogue regimes and terror groups.