Last week epitomized the highs and lows of hoping for an improvement in US-Iran relations. A BBC report on Sept. 5 that Iran’s Supreme Leader Ali Khamenei had approved Iranian cooperation with the US military in the fight against ISIS was met with near elation in many quarters. Some analysts (myself included) felt this announcement would clarify the strategic value of normalized US-Iran relations for the publics and policymakers of both countries. But after the ensuing Iranian denials that cooperation was in fact approved, the Americans went even further by denying even the possibility of formal cooperation. A Sept. 8 State Department briefing reiterated the exclusion of Iran from the broad 40-nation coalition announced by President Obama to combat ISIS, and Secretary of State John Kerry’s Sept. 12 assertion in Ankara that including Iran “would not be appropriate” because of its involvement in Syria and its alleged status as a “state sponsor of terror in various places” put the icing on the cake.

Perhaps unsurprisingly, Iranian hardliners have taken heart from this very public snub. Even Marziah Afkham, the spokesperson for the Foreign Ministry, a stronghold of pragmatists who favors improved relations with the West, felt compelled toregister “serious doubts about [the coalition’s] seriousness to fight against the root and true reasons for terrorism.” She noted without elaboration that “[s]ome of the countries in the coalition are among the financial and military supporters of terrorists in Iraq and Syria.”

Unlike US policymakers, Iranian statesmen—and the wider public—have a long memory. As the recent anniversary of Sept. 11 reminds us to “never forget,” we can do little but remember the lives lost and contemplate how the United States was drawn into a global conflict with religious extremists 13 years ago. For Iranians, however, the fateful date came four years before.

The Taliban reached global prominence in 1998, a year when its fighters launched a devastating offensive in northern Afghanistan. Much as the Islamic State in Syria and Iraq (ISIS) last month swept across northern Iraq, forcing the Kurdish Peshmerga to retreat to within 40kms of Erbil, the better-armed and better-organized Taliban overcame all resistance by the Iran and Uzbekistani-backed coalition there during that summer. On Aug 8, it captured Mazar-e Sharif, Afghanistan’s fourth largest city, located just 100km from the border with Uzbekistan. Overwhelming local militias, Taliban troops and their allies massacred an estimated 2,000 Hazara civilians in what Human Rights Watch called “one of the worst atrocities of Afghanistan’s long civil war.” In addition, they stormed the Iranian consulate, killing a journalist and ten members of the diplomatic mission, despite assurances from the government of Pakistan, a chief sponsor of the Taliban at the time, that diplomats would not be targeted.

The diplomats’ murder—as well as the massacre of civilians—outraged both the Iranian regime and the broader public. Foreign Ministry officials mourned their fallen colleagues, whom they celebrated as martyrs akin to those who died ”defending the borders of this great country during eight years of holy defense” during Iran’s 1980-88 war with Iraq. An official statement broadcast on Iranian state television asserted Iran’s ”right to defend the security of its citizens” and warned that “the consequences of the Taliban action is on the shoulders of the Taliban and their supporters.”

For Iran, there was no question that the Taliban enjoyed the support of two states: Pakistan and Saudi Arabia. Without significant financial support from Saudi sources and the help of Pakistan’s Inter-Services Intelligence (ISI), the Taliban would not have been able to stage such a brutal offensive. While it had taken Kabul two years before, the conquest of Mazar-e Sharif consolidated the Taliban’s position as the ruler of virtually all of Afghanistan, a status that no doubt contributed to its increasingly close cooperation with al-Qaeda.

Iran responded by building up its forces along the Afghan border and conducting major military exercises. But the Islamic Republic felt unable to commit to a costly and unpredictable war in Afghanistan unilaterally. It was only three years later, with 9/11, that the US came to realize the full nature of the threat posed by al-Qaeda and its Taliban collaborators.

Suddenly, Iran and the United States had a common enemy. As Washington mulled its strategy to rout the Taliban and destroy al-Qaeda, officials in Tehran reached out to offer strategic support. Years of experience in Afghanistan had given the Iranians deep insight into how the Taliban operated in the ethnically and geographically complex nation.

The secret discussions that occurred between American and Iranian officials in the weeks that followed were the highest-level talks held between the two countries since the 1979 Iranian Revolution and the subsequent hostage crisis. Many analysts believed that the new-found alignment of strategic interests, combined with President Mohammad Khatami’s reformist policies and conciliatory tone, would spur the US and Iran to normalize relations and actively cooperate against the terrorist threat.

In a grave blunder, however, neoconservatives and other hawks in the Bush administration opposed collaboration with Iran, thus depriving coalition forces of a valuable ally. Two months later, in a triumph of politics over pragmatism, Bush gratuitously lumped Iran together with Iraq and North Korea in his infamous “axis of evil,” a move that greatly strengthened hard-line forces in Tehran who had long argued that Washington simply could not be trusted.

It is striking how this situation mirrors that faced by the US and Iran today as both countries face the threat posed by ISIS. The Rouhani administration has opened the door to reconciliation, and the rise of reinvigorated Sunni extremism in the region gives Washington and Tehran a common enemy. Indeed, Iran has sent arms and advisers to Iraq to help the Peshmerga and Iraqi forces roll back ISIS’s recent advances.

Nonetheless, the US remains unwilling to include Iran in its coalition efforts. This position has given hardliners in Iran yet another opportunity to instill doubts about Washington’s sincerity and trustworthiness. Unsurprisingly, the events of 1998 and 2001 weigh heavily on Iran’s collective memory. Indeed, the conservative website Javan Online last week recalled “Iran’s bitter experience of cooperation with the US in Afghanistan,” citing it as reason to dismiss cooperation with Washington against ISIS. The conservative refrain that members of the coalition are “among financial and military supporters of terrorists” is also rooted in the historical memory of the 1998 offensive. Iran also continues to view Saudi Arabia as a key source both of funding for ISIS and other radical Sunni groups and of their intolerant and violent ideology, just as it was for the Taliban.

That Riyadh and its Gulf allies should be treated by Washington as central partners in the anti-ISIS coalition, while Tehran is excluded from any formal participation is particularly galling to Iranians who have suffered the brunt of US sanctions. Not only is this, in their view, illogical. To them, it also suggests that Washington is simply unable to learn from its past mistakes.

–Esfandyar Batmanghelidj is a founding partner of the 1st Europe-Iran Forum, a conference focused on commercial opportunities in Iran to be held in London in October. He has conducted extensive research on Iranian political economy and social history.

Photo: Iranian Foreign Minister Javad Zarif shakes hands with US Secretary of State John Kerr on July 14, 2014 in Vienna.