The rapidly escalating conflict between Saudi Arabia and Iran, sparked by the execution of a Saudi Shiite activist, may seem like the natural outgrowth of a decade's Sunni-Shiite tensions. But more than denominational differences, what's driving the open conflict is the Saudis' deepening fear that the U.S. is shifting its loyalties in the Persian Gulf region from its traditional Saudi ally to a gradually moderating Iran. And in a sense, they're right: Although the U.S. is a long way from becoming an instinctive Iranian ally, the nuclear deal has led Washington to start broadening its base in the Gulf, working with Iran where the two sides have overlapping interests. Of which there are many these days.
The Saudis executed the activist, Nimr al-Nimr (it means Tiger the Tiger, by the way, which could possibly be the best name ever), last weekend because they wanted to send a message to the country's Shiite minority and neighbors, and because they thought they could get away with it.
The outspoken al-Nimr symbolized the possibility that Saudi Shiites might never fully accept their second-class status and, worse, might seek autonomy or independence in the event of the Saudi state's weakness. The Saudis seem to have calculated that if Iran made any noise about the execution, it would not have leverage to do anything about it. Undoubtedly the Saudis knew the Americans wouldn't be best pleased with them for killing a nonviolent activist — but again, they must've thought it wouldn't matter.
Executing al-Nimr was thus probably intended to demonstrate that the Saudis can go it alone, making security-related decisions without worrying what their neighbors or the U.S. think. If that's right, the execution was an indirect signal that Saudi Arabia is feeling isolated, and that if isolated, it will act unilaterally.
Here the Saudis overplayed their hand. The Iranians reacted cleverly. First, the government stirred up public sentiment by condemning the execution. Then, it allowed angry protesters to storm the Saudi Embassy in Tehran. Finally, the Iranian government shut down the protest, made arrests and issued public statements disclaiming responsibility for what had happened.
To be sure, the Iranian government is a complex organism with many moving parts, and the whole response likely wasn't planned or coordinated by a single actor. But the result was highly effective. It showed the Saudis that Iran took the execution as directed toward it. And it simultaneously gave other countries the cover they would need to side with Iran.
The Americans, rather remarkably, took the Iranian side. U.S. Secretary of State John Kerry let it be known that he was talking to his Iranian counterpart, Mohammad Javad Zarif. In the past, a U.S. secretary of state would've reached out solely to the Saudi foreign minister, not least because there were no official diplomatic ties to Iran. Meanwhile, a former deputy CIA director, Michael Morell, publicly praised the Iranians for their handling of the situation in Tehran. This was downright astonishing, given Americans' historical associations with embassy occupation there.
These reactions show that Saudi worries about American abandonment are to a degree justified. After the Iran nuclear deal, American foreign policymakers can look at an episode like the al-Nimr affair and ask: Whose fault is this? If the answer is the Saudis, the U.S. can now afford to side with Iran.