In the midst of Iran's recent nuclear deal with world powers, Tehran's regional competitors will not sit idly by without attempting to curb the expansion of Iranian influence.
Despite a number of common interests, Turkey and Iran are natural competitors. Although Kurdish containment is one such shared interest, the Kurds are also used by each to undermine the other. While Turkey is predominantly Sunni and Iran predominantly Shiite, it is important to note that Ankara and Tehran seek to establish dominance over a region that is predominantly Arab. For many Arabs, choosing between Turkish or Persian rule is like choosing between death by drowning or by immolation.
Unlike Turkey, Saudi Arabia has relatively few if any shared interests with Iran. The kingdom is an Arab, Sunni power, and the Wahhabism sect of Islam to which most Saudis subscribe views Shiites with deep suspicion. With a Shiite minority making up between 10 percent and 15 percent of its population, and with Iraq no longer a bulwark against Iran's ambitions, Saudi Arabia rightly sees itself on the front line of the conflict with Iran. Because the Iranians are already trying to provoke minority groups in Saudi Arabia, the Saudis will likely at least attempt to embolden an autonomous Kurdistan capable of affecting regional economic and security issues — even though supporting the Kurds will mar Riyadh's relationship with Ankara. After all, though both are Sunni powers, Saudi Arabia has almost as little interest in seeing Turkey dominate the Middle East as it does Iran.
Egypt, like Saudi Arabia, is an Arab Sunni power, but one much more constrained in its actions than is Turkey or Saudi Arabia. Egypt is facing serious internal issues as it tries to roll back a subsidy regime, elect a parliament, contain social unrest, and manage multiple jihadist threats in the country. Still, Egypt and Saudi Arabia have increased cooperation in recent months and may try to pool their resources to protect the Arab heartland of the Middle East. A joint Arab defense force under development could easily become part of this plan and is one of Cairo's ways of attempting to maintain a prominent role in the regional alignment.
Overall, the Iran nuclear deal will not mean less violence or war; it will mean more. Conflict in the Middle East will become increasingly about Turkey, Iran, Saudi Arabia and Egypt using various groups to compete with one other for regional influence.