A CANCER IS SPREADING: ISIS claims responsibility for suicide bombing in Saudi Arabia. ISIS’s targeting of Saudi Arabia means awful things for the U.S.:

What these attacks say is that Riyadh doesn’t have the comforting control over its land that Americans like to believe it does. And if the royal family doesn’t have its territory as buttoned down as Washington assumed, what other weaknesses has it been masking? What other vulnerabilities now are on view? . . .

The real reason is that it casts into doubt all of the mythology America has created around its favorite autocratic kingdom. The royal family operates a government that is truly authoritarian. It abuses the rights of its citizens. It discriminates against women. It does frightfully little to protect its minority communities. Beheadings. Disappearances. But, damn, it sure is quiet over there. And man, that’s gotta mean those guys are as tough as we need them to be, that they are the mighty Sunni power that’s going to help us do one thing in particular—keep Iran in check.

It’s about to get very noisy. And Iran won’t be kept in check; it is emboldened.