The Iranian flag flies in front of a UN building  at the International Center in Vienna, Austria,  in 2014. (AP Photo/Ronald Zak)

This post is part of the “International Relations and a new Middle East” symposium.

Saudi Arabia is fighting in Yemen and supporting rebels in Syria in part to push back against Iranian influence. Saudi’s highly vocal efforts can distract from one of the most notable yet underappreciated elements of the current Middle East: the lack of a strong regional alliance against Iran. The absence of such a countervailing coalition is explained by what political scientist Randall Schweller termed “underbalancing,” the inability or unwillingness of states to form the kind of blocking alliances that balance of power theory would predict.

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Iran is the undoubted geopolitical winner in the region’s upheavals. It is the most influential player in Iraqi politics, nurturing close relations with the Abadi government, sponsoring if not controlling a number of Shiite militias and maintaining a cooperative relationship with the Kurdish Regional Government (exemplified by its supply of arms to the KRG during the Islamic State offensive last summer). Iranian support also has been essential to the preservation of the regime of Syrian President Bashar al-Assad in Damascus, and its client Hezbollah remains the dominant force in Lebanese politics. While Tehran’s relationship with the Houthis is not as strong or as direct as that with Hezbollah or the Iraqi militias, the success of the Houthis in Yemen further contributes to the regional sense that Iran is on the march. Efforts by other regional powers to challenge Iranian gains have to date all failed, whether Turkish and Saudi support for the Syrian opposition, Saudi financing of the March 14 coalition in Lebanon and military aid to the Lebanese government, or the current Saudi air campaign against the Houthis.

According to balance-of-power logic and by its “balance of threat” alternative, the region should have witnessed a Turkish-Saudi-Israeli alignment aimed at Iran. Pooling resources makes sense since no single state can match Iran’s power. Israel and Saudi Arabia both seem to identify Iran as their major threat, and although Turkey may not be as focused on Iran, it still worries about Iran’s growing regional reach. A Turkish-Saudi understanding makes perfect sense by the sectarian logic that many believe is driving regional politics, as both are Sunni states. But neither the trilateral nor the bilateral balancing alignment against Iran has emerged.

The biggest impediment to such a grand regional alliance is not the United States. Washington would like to see Iranian regional influence contained, even as it is negotiating with Tehran on the nuclear issue, and is hardly standing in the way of a regional alignment against Iran. Even if it were, there is little evidence that Turkey, Israel or Saudi Arabia are taking their cues from the Obama Administration these days.

Rather, the primary reason for underbalancing against Iran is found in the realm of ideas. Iran does not simply represent a power challenge to its Arab neighbors. It also challenges the legitimacy of their domestic political systems through its rejection of monarchy and its strong appeal to many fellow Shiites. It refuses to accept the American-led regional order that has prevailed since the end of the Cold War and thus directly challenges the foreign policy of many of its neighbors.

The potential members of an anti-Iranian coalition do not share common ideas about how politics in the region should be organized and are wary of cooperation with each other. Saudi Arabia and Turkey represent very different models of domestic political order. The Saudis support fellow monarchs and discourage democratic reform both at home and abroad. Turkey under AKP rule has supported a version of populist, Islamist democratic reform in the Arab world, particularly by backing Muslim Brotherhood movements. Meanwhile, the Israel of Prime Minister Benjamin Netanyahu is following a barely-veiled colonialist project in the West Bank that makes it anathema to public opinion throughout the Muslim world.

The Middle East is not simply a multipolar region in terms of power. It is also multipolar ideologically. Political scientist Mark Haas provides a framework to understand why regions with multiple and competing political ideologies at play are more prone to underbalancing. Haas argues that in systems characterized by ideological bipolarity, like the Cold War, alliances will tend to follow ideological lines (NATO vs. the Warsaw Pact) and be very stable. However, when there are multiple ideological principles at work, state leaders will eschew alliances that seem logical from a power perspective because they dislike and fear the ideological stance of a potential ally. His paradigmatic example is 1930s Europe, where the Western democracies and the Soviet Union were unwilling to ally against the growing power of Nazi Germany.

Haas’s model of ideological multipolarity fits the current Middle East like a glove. Not only do the Iranians, Saudis and Turks present mutually incompatible political models for their neighbors, but the Islamic State adds another model to the mix. It is propounding a transnational salafi jihadist model that shares elements of Saudi Arabia’s conservative version of Islam, Iran’s revolutionary rejection of the current regional system and AKP Turkey’s Sunni Islamist populism — yet is a direct threat to all three states. This ideological multipolarity puts serious obstacles in front of what pure power considerations would deem “logical” alliances.

The Saudis seem uncertain about who is their greater threat, Iran or the Islamic State. The seemingly natural Turkish-Saudi balancing alliance against Iran is impeded by Saudi fears that the Turkish model of populist, democratic Islamism will aid the Muslim Brotherhood in the Arab world. While the Saudis clearly want to roll back Iranian influence, they have also declared the Muslim Brotherhood a terrorist organization. Turkey partnered with Qatar, another regional player that had bet on the Muslim Brotherhood, to encourage Islamist opposition to the Assad regime. But it now seems to be torn between the goal of Assad’s removal and the fear that the Islamic State has become the more salient threat to Turkish security. Ankara, which historically has maintained decent relations with Israel, has now chosen to distance itself in a very public way from Jerusalem for ideological and domestic political reasons. The desires of some of Israel’s friends in the United States to foster a Saudi-Israeli connection against both Iran and the Islamic State have not been realized. Riyadh cannot contemplate an open relationship with the Netanyahu government because of its fears of the domestic political consequences of such an alliance.

The perceptions of ideological threat that underpin the barriers to alliance formation in ideological multipolarity are not set in stone. It took a while, but eventually the Western democracies and the USSR did join forces against Nazi Germany. There are a few tentative indications that just such a perceptual change may be afoot in the Middle East. The new Saudi King Salman seems to be less focused on the political threat to the Saudi regime posed by the Muslim Brotherhood than was his predecessor. Turkish President Recep Tayyib Erdogan might be feeling his current regional isolation more than in the past. His February visit to Riyadh occasioned speculation from both sides that a rapprochement was in the works. The capture of Idlib by a coalition of Islamist elements of the Syrian opposition at the end of March might signal a new willingness for Saudi and Turkish clients in Syria to cooperate. The Yemeni Islah Party, which includes the Yemeni Muslim Brotherhood, recently announced its support for the Saudi bombing campaign against the Houthis.

These scattered events raise the possibility that the new Saudi king is reevaluating his predecessor’s ranking of the threats faced by Riyadh, downplaying the Muslim Brotherhood threat to Saudi domestic regime security and opening up the possibility of a Turkish-Saudi alliance against Iran. A successful conclusion of the P5+1 talks with Iran could further increase regional balancing incentives against the Iranians. If the Saudis and the Turks both decide that Iran presents a bigger threat to them than any other regional player, regardless of a successful P5+1 negotiation, then “underbalancing” against Tehran might end. However, a possible consequence of the formation of such an alliance might be more space for the Islamic State and al-Qaeda affiliates to maneuver in Syria, Iraq and elsewhere. More likely, the plethora of contesting ideological positions in the Middle East today will prevent decisive alliances from being formed against any regional power – Iran or the Islamic State. “Underbalancing” is likely to characterize the region for some time.

 F. Gregory Gause III is a professor of international affairs and the John H. Lindsey ’44 Chair at the Bush School of Government at Texas A&M University and a nonresident senior fellow at the Brookings Doha Center.