U.S. officials: ISIS Trying to Topple Saudi King

Current and former US officials said Thursday that a recent ISIS attack on the tomb of Mohammed in Saudi Arabia — Islam's second holiest site — shows the terror group is now directly challenging the kingdom's ruling family and trying to topple the monarchy.
The Saudi king's titles include 'Protector of the two Holy Cities, said one senior U.S. counterterrorism official. "The message of the attack is that that protection doesn't exist."