On the eve of the centennial of Iran’s first modern revolution, the country is experiencing the latest in a series of popular eruptions against an oppressive government. It was 100 years ago this month that Iranian freedom fighters were marching on Tehran to depose an autocrat they could no longer abide. By mid-July 1909, this army of varied tribal, ethnic, and secular democratic mujahedin would capture the capitol and send the Qajar monarch, Muhammad Ali Shah, packing to Russia, placing his young son on the throne of a revived but still infant constitutional monarchy. Iran’s early democracy, however, expired within two years because of reactionary pressures and the revolutionaries’ inability to live up to their principles, a fact that should instill some caution regarding attempts to discern the many twists and turns such challenges to an existing order in Iran can take.

Since the late 19th century, the major civil disturbances that have repeatedly roiled Iran have shared a number of features that can put the prospects of the current anti-government demonstrations into perspective. Though there are many factors that have influenced the outcomes of past Iranian protests--including the strength of opposition leaders and complaints about foreign domination --history indicates that the most important factor affecting the success of nationwide dissent is the perceived strength of Iran’s security forces. Unfortunately, this history does not bode well for the Iranians now demanding a greater voice in how they are governed.

The Qajar-era Iranian military, who unsuccessfully tried to fend off the assault on Tehran in 1909, was under-funded, poorly trained and equipped, badly led, and often sympathetic with the mujahedin fighting for the constitution. Though the army grew stronger in the following decades, the short-lived autonomous republics of Gilan in 1920-21 and Azerbaijan and Mahabad (Iranian Kurdistan) in 1945-46 were able to overcome the Iranian armed forces with the support of Soviet Red Army units.

By the time that the last shah of Iran, Muhammad Reza Shah Pahlavi, battled Grand Ayatollah Ruhollah Khomeini in the 1970s, the Imperial Iranian Armed Forces were large, well-armed, and lavishly funded. But they were undermined by the vacillating monarch’s shifts between repression and accommodation, which included the punishment of some security officials for their harsh measures. The shah’s undercutting of his generals aggravated their already poor leadership and hurt the morale of the junior officers and enlisted men.

More important, Khomeini’s revolutionaries used an array of clever tactics to neutralize the armed forces. Successful attacks on the security forces showed that the regime was vulnerable, and often intentionally provoked government reactions that incited more unrest. Khomeini also ordered his followers to embrace the military rank-and-file and bring them to the revolutionaries’ side through fraternization and propaganda. Additionally, in more of a choke hold than an embrace, intimidation and psychological warfare were used to undermine the troops’ loyalty. There were echoes of both of these tactics during the fourth day of this month’s protests when some of the demonstrators offered flowers to security force personnel shortly before other protestors attacked a paramilitary base.

In the past, the armed forces have not uniformly supported the ruling Islamic Republic. For much of the 1990s, the senior commanders of the Islamic Revolutionary Guard Corps (IRGC), the main pillar of the clerical government, could not be certain of the rank-and-file’s loyalty. During anti-regime riots in Qazvin in 1994, for example, some IRGC units refused to carry out commands to use force to reestablish order. And most of the security services, sharing the views of their families and peers, seemed to have supported former president Mohammad Khatami, the moderate cleric who sought to reform Iran’s government. In the 1997 presidential election, for example, they voted for Khatami in percentages similar to the rest of the country.

In response to this lack of loyalty, the regime developed various new units, including special male and female Basij paramilitary units, to handle violent unrest. The clerics relied on poor Iranians--who were still beholden to the regime for subsidies, work, and religious guidance--to staff these units, which have been trained and equipped for riot control and containing internal unrest. These Basij units, which back up the national police service, are the firebreak against serious regime threatening unrest.

Despite regime efforts since the 1999 student riots to inoculate the security services against divided loyalties, the prospect cannot be discounted. The current IRGC commander, Mohammad Ali Jafari, publicly announced last year a reform program for the Guard that aimed to revive its revolutionary spirit, and an official IRGC statement on the eve of the election rejected the suggestion that there was a gap between Guard commanders and their personnel. But leading up to the election, 59 former senior IRGC officers publicly announced their support for presidential candidate and current opposition leader Mir Hosein Mousavi, and former Guard commander and defeated conservative presidential candidate Mohsen Rezai has joined Mousavi in demanding that the election results be overturned.

Finally, throughout Iran’s modern history civil disturbances have achieved the most when the government leadership was perceived as fragile or uncertain. Muzzafar al-Din Shah, the initial target of the 1905-1911 revolution, was dying when he agreed to Iran’s first constitution and legislature in 1906. The celebrated former prime minister Mohammad Mossadeq, who won renown by besting the British and nationalizing Iran’s oil over the shah’s objections in the early 1950s, had become increasingly autocratic by 1953, which had estranged him from much of his political base and left him vulnerable to a coup by his pro-shah enemies in the military and among the Iranian elite. Muhammad Reza Shah Pahlavi was sick with cancer and an increasingly indecisive leader as he faced off against the iron-willed Khomeini.

Iran’s current leader, the 70-year-old Supreme Leader Ayatollah Ali Khamenei, has enjoyed the strong backing of the IRGC as he has consolidated power over the past 20 years. The overt support for him shown by the security forces will be one of the most important indicators of where he stands with the Iranian people--and, in turn, will provide some insight into how bold they can be in pressing for change.

Steven R. Ward is a senior Middle East analyst for the U.S. government. He is the author of Immortal: A Military History of Iran and Its Armed Forces (Georgetown University Press, 2009). The views expressed in this article are those of the author and do not reflect the official policy or position of any U.S. government agency.

By Steven R. Ward