BEIRUT—A recurrent theme in history, literature and, lately, engagé academics is that of brash Westerners trying to possess the East and failing—or at best leaving a transitory mark. From Alexander the Great to George W. Bush, few have successfully reshaped the Middle East in their own image. In his book "Figures de Proue," the great French historian René Grousset used an excellent formulation to express a discordant interplay between West and East. Describing how the Orientalization of Hellenism under Alexander had removed from Hellenism its "superior humanism," even though concepts were still being expressed in Greek, Grousset wrote: "As so often in history, words would, henceforth, lie to [the reality of] things."
A similar thought came to my mind when reading from a letter written at the end of December by Iran's supreme guide, Ali Khamenei, to religious pilgrims. In his missive, Supreme Guide Khamenei condemned all those who criticized Hezbollah, who believed in the "illusory danger" of a so-called Shiite arc in the Middle East, who sought to bring down the "Islamic government" in Iraq, and who applied pressure against Hamas. They were "criminals who will be remembered in Islamic history, and by future generations, with hatred and anger as agents of the perfidious enemy." If Iran's supreme guide thought the Arab world would welcome his words, his pushing of ideological buttons in expectation of a rallying response among his listeners, then he underestimated how the Arabs' growing suspicion of Iran means they see his words increasingly as "lying to things."
Western grand projects frequently succumbed to Middle Eastern intransigence. But as Shiite Iran makes a bid for regional hegemony, its leadership should consider that the mostly Sunni Arabs may be as resistant to hubris coming from the East as from the West. That Arab regimes are weak, and because of their autocratic nature enjoy only dubious legitimacy at home, might only harden their resistance. Facing what they see as an Iranian threat, unsure of their ability to contain it, with or without American assistance, aware of the tenuousness of the oil weapon, these regimes may ultimately resort to the most ready defense at hand, one that would briefly enhance their influence: Sunni sectarian mobilization.
Take Lebanon and the Palestinian territories. Since December, the Lebanese government of Prime Minister Fouad Siniora has been facing opposition demands to resign. While that opposition includes members of all religious groups, its vital force and street muscle are the Shiite supporters of Hezbollah. That's why Lebanese viewed the open-ended protests through a sectarian prism. The Sunni community rallied to the side of the government, whose prime minister and a majority of ministers are allied with or members of Saad Hariri's Future Movement, which now represents most of Lebanon's Sunnis. Mr. Siniora, in order to protect himself, asserted that Hezbollah was bent on staging an Iranian- and Syrian-backed coup d'état, by which he effectively meant a Shiite coup.
Not surprisingly, the Sunni Arab regimes entered the fray to bolster the government. They dispatched Arab League secretary general Amr Moussa to Beirut to mediate. Sunni-Shiite tensions remain alarmingly high, and on Tuesday the opposition escalated its confrontation with the government by cutting off roads. Sunnis and Shiites clashed in some neighborhoods, though neither Hezbollah's leader, Hassan Nasrallah, nor Mr. Hariri (nor, for that matter, their respective sponsors in Iran and Saudi Arabia) wants to let the sectarian genie out of the bottle. However, as political interests kick in, sectarianism may emerge as the default weapon that the parties, in Lebanon and outside, may use against each other.
Something similar is happening in the Palestinian territories. Palestinian Authority President Mahmoud Abbas's recent call for early elections, like his ongoing differences with Hamas, transcends local politics. His aim is to check Hamas at a time when the organization is consolidating its ties with Tehran. Mr. Abbas failed to reach an agreement last weekend in Damascus with exiled Hamas leader Khaled Mashal, who controls Hamas from Syria, Iran's main Arab partner. In rallies in Palestinian areas, the president's Fatah movement has taken to taunting members of the rival Hamas by calling them "Shiites," though they are Sunni.
Wherever they look today, Arab Sunnis see setbacks, real or imagined. In Iraq, where Sunni dominance ended in 2003, Saddam Hussein's hanging provoked an angry sectarian response. Saudi Arabia's King Abdullah recently warned Vice President Dick Cheney that the kingdom would openly support Iraqi Sunnis if the Americans withdrew. In the Palestinian territories and Lebanon, accusations are now routine that Hezbollah and Hamas are serving Tehran's agenda. In Syria, a minority Alawite regime rules over a mostly Sunni society. In Bahrain, the Shiite majority is affirming itself against a Sunni royal family. And in Saudi Arabia, the oil-rich Eastern Province is home to a sizeable though marginalized Shiite minority. While the notion of a Shiite arc stretching from Iran to Lebanon is crude, Ayatollah Khamenei overlooked that many Arab Sunnis are buying into that view, and do not see themselves as criminals for doing so.
A primarily sectarian Arab counter-reaction to expanding Iranian power would be a disaster. It might halt Iran and its comrades in the short term, but Arab regimes could soon become sorcerers' apprentices, swallowed by the forces they unleash. Iran, wrongly believing that popular anti-Israeli and anti-American sentiment would overcome Sunni suspicions of their true intentions, should realize what a Sunni backlash would mean for their security. Once opened, the floodgates of Sunni-Shiite antagonism could become a Leviathan, sweeping away the fragile reality on the ground: Even in societies where Sunnis and Shiites now peacefully coexist, sectarian discord would become the norm.
Then there is the United States. Whatever one thinks of the war in Iraq, it will soon become obvious that it was easier for the Americans to enter the country than to leave it. If a departure leads to metastasizing sectarian hostility throughout the Middle East, then the U.S. will have to seriously rethink its strategy. Whatever else happens, the one assured winner of such a fracas would be the Islamists. Only democracy could prepare Arab states to withstand Iran without recourse to sectarianism. But the Bush administration seems to have abandoned that inventive undertaking for the region.
A chain of sectarian wars is not inevitable. But the only way to avoid it is for all sides to understand the existential red lines of the other sides. Iran's overconfidence is no easier for the region to stomach than was America's. For the first time in decades, the nationalism, tribalism or regime-sponsored Islamism of the Sunni Arab states seem incapable of steeling them against a resurgent Iran, but also its allies, striving to fill the vacuum of fading Arab power. Only these regimes' Sunni identity, an offended Sunni identity at that, might do so. The problem is that what shields them will likely lead the Middle East into further disarray.