Saudi Arabia is hoping the Yemeni rebel alliance is fracturing, which could open the door for the Saudi alliance to escape the quagmire Riyadh is stuck in. It's a long shot, and not a viable strategy for Washington.

The Zaydi Shiite Houthi rebels aligned with former President Ali Abdullah Saleh, 75, three years ago to seize Sanaa from the collapsing government of his onetime deputy and successor Abed Rabbo Mansour Hadi. It was a strange and awkward alliance from the start. Saleh, also a Zaydi, had waged war against the Houthis for a decade before the Arab Spring, often with Saudi assistance. The Houthis backed Saleh's removal from power in 2012 — this time with Saudi assistance. In 2015, the two rivals saw a convergence of interests to oust Hadi and take control of North Yemen. At first it was a clandestine partnership until the full extent of Saleh's betrayal of his former deputy, and the Saudi-engineered deal that put Hadi in power, became apparent.

The Saudi relationship with Saleh goes back to the early 1960s when he backed the pro-Egyptian coup that plunged Yemen into civil war for years, pitting the Egyptian-backed republicans against the Saudi-backed royalists. Saleh got his combat training fighting the Saudis and the royalists, taking power in a coup in 1978. Twelve years later he united North and South Yemen, but then backed Iraq and Saddam Hussein in the Kuwait crisis. The Saudis swore revenge and threw a million Yemeni workers out of the kingdom.

In 1994, the Saudis engineered the south Yemenis' secession from Saleh's united Yemen by backing the former communists who had lost power in unification. With the help of jihadi groups, Saleh outfought the southern rebellion, restored unity and humiliated the kingdom. It was a very bitter pill for the Saudis.