We've entered the post-ISIS phase in the Middle East

(CNN)Out of the blue, from an undisclosed location in the Saudi capital of Riyadh, 47-year old Lebanese Prime Minister Saad Hariri announced his resignation Saturday afternoon. Claiming to have been the target of an assassination plot (which his own security forces deny), he left little doubt as to those responsible for his surprise decision. "Wherever Iran settles," he said, "it sows discord, devastation and destruction, proven by its interference in the internal affairs of Arab countries."

The ground war against ISIS may be coming to an end, but the long-simmering rivalry between the Kingdom of Saudi Arabia and the Islamic Republic of Iran now threatens to boil over in Lebanon, a country where both Tehran and Riyadh accuse one another of interfering in Beirut's affairs, while doing exactly that.