Shutting Out Iran Will Make the Afghan War Even Deadlier
Washington's hard line gives Tehran every reason to fund the Taliban.
Six months after the Trump administration withdrew from a multilateral nuclear deal with Tehran, triggering an initial reimposition of sanctions, Washington has reinstituted additional punitive measures on Iran. U.S. President Donald Trump described the latest sanctions, which went into effect on Nov. 5 and target the key Iranian industries of oil, banking, and shipping, as the “toughest ever.”
Washington’s ever-hardening line on Iran is a big mistake—and not just because it strains alliances with NATO, undermines global nonproliferation, and risks destabilizing the Middle East. Scuttling the nuclear deal and sanctioning Tehran could also cause America’s unending war in Afghanistan, Iran’s eastern neighbor, to escalate violently.
Washington has already telegraphed its concern about the Taliban’s ties to Tehran. Last month, the U.S. Treasury Department and six Persian Gulf nations sanctioned seven Taliban leaders and two officers with Iran’s Islamic Revolutionary Guard Corps. The stated goal is to “disrupt Taliban actors and their Iranian sponsors that seek to undermine the security of the Afghan government.” U.S. Treasury Secretary Steven Mnuchin described “Iran’s provision of military training, financing, and weapons to the Taliban” as “yet another example of Tehran’s blatant regional meddling and support for terrorism.”
But with no prospect of improving relations with the United States, at least as long as Trump remains president, Iran has a strong incentive to increase military support to the Taliban, a persistent thorn in America’s side. The Afghan Taliban are already a beneficiary of episodic Iranian military assistance, but this surge in support could come at the very moment when Washington is making a full-bore effort to bring the insurgents to the peace table.
Backing the Taliban is a relatively cost-free way to retaliate for the canceled deal, and the covert nature of this assistance gives Tehran plausible deniability. More funding would also bolster Iran’s influence over the Taliban—a useful hedging strategy if the United States leaves Afghanistan. Additionally, it strengthens the Taliban’s capacity to target the Afghanistan affiliate of the Islamic State—a group opposed by both Iran and the Taliban, and with which the latter regularly clashes violently.
At first glance, the idea of Iran-Taliban cooperation may seem strange. Iran is a Shiite state; the Taliban are Sunni militants. Tehran enjoys considerable influence among Afghanistan’s Shiite Muslims, who were often targeted for murder by the Taliban during the Afghan civil war in the 1990s. In 1998, after nine Iranian diplomats died in an attack on their consulate in the Afghan city of Mazar-e-Sharif, Iran mobilized 200,000 troops on its border with Afghanistan and nearly went to war with the Taliban, which ran the country at the time.
Tehran has also worked closely with the Afghan government in Kabul. At the 2001 Bonn Conference, which cobbled together Afghanistan’s first post-Taliban government, Iranian negotiators played an instrumental role in fashioning a final agreement. Iran and Afghanistan signed a strategic cooperation accord in 2013. In 2016, they inked a deal with India to develop a new transport corridor project stretching from the southern Iranian port of Chabahar into Afghanistan.
And yet, as I explained two years ago in Foreign Policy, none of this has stopped Tehran and the Taliban from having a long-standing relationship. When Mullah Mansour, the head of the Afghan Taliban, was killed in a drone strike in 2016 while driving in Pakistan, he was returning from a trip to Iran—where the Taliban opened an office in 2012.
Despite all their bloody differences, a common U.S. enemy is enough to bring the two sides together. Iran has long feared the United States will use Afghanistan as a staging ground for a strike on its nuclear facilities. The Trump administration’s hard line on Iran only deepens Tehran’s anxieties about the U.S. presence on its eastern flank.
Over the last decade, NATO forces have periodically intercepted Taliban-bound Iranian arms shipments. By 2015, according to Afghan and Western officials, Iran was increasing its supply of arms to the Taliban—while also starting to fund, recruit, and train their fighters.
Such allegations have intensified in recent months. Officials in western Afghanistan have claimed that Iran’s Revolutionary Guard has provided funding, shelter, money, and arms to Taliban fighters. The Taliban itself has acknowledged Iranian assistance. In July, a Taliban political advisor disclosed to the Times of London that in May, as Trump was preparing to pull out of the nuclear agreement, the Taliban reached a deal with Tehran to send fighters to Iranian military academies for six months of “advanced training.”
Iranian support for the Taliban appears most consistent in the western province of Farah, which borders Iran. In February, local officials there said they had seized Iran-made weapons. Then, this past spring, Taliban forces waged a furious offensive in Farah. They seized areas close to the provincial capital, also called Farah, and killed dozens of police and soldiers. They also penetrated the provincial capital itself and advanced on key government facilities, including an army recruitment center and a provincial headquarters for Afghanistan’s intelligence agency. This latter offensive took place in mid-May, just days after Washington withdrew from the nuclear agreement with Iran. While Afghan and American forces eventually repelled the Taliban advance, insurgents are still on the offensive in Farah. Earlier this month, a Taliban attack there killed 20 Afghan border troops.
There is a precedent for Iranian military cooperation with the Taliban in Farah. Back in 2016, according to reporting from the New York Times, Iran helped orchestrate a raid on the provincial capital. Four Iranian commandoes were killed in the operation, and several wounded insurgents were brought to Iran for treatment.
Farah is a logical place for Iran to step up its support. In a worst-case scenario, this could conceivably help the Taliban seize the provincial capital, as well as giving them potential control of a sizable portion of a flourishing drug trade, a key source of the insurgency’s funding. According to the United Nations, opium production in Farah increased by about 40 percent between 2016 and 2017. Stepped-up Taliban support could conceivably spread to Herat and Nimroz, the other Afghan provinces bordering Iran, and where insurgents already enjoy deep influence and some outright control.
The Taliban—buoyed by overmatched Afghan security forces; a weak, dysfunctional Afghan government; record-breaking opium harvests; and safe havens in Pakistan—are a strong and emboldened fighting force. Greater Iranian support for the insurgents would make an already-formidable Taliban even stronger—further disincentivizing them to stop fighting and start negotiating an end to the war. For a U.S. government fervently pursuing peace talks with the Taliban, stepped-up Iranian military support for the insurgents couldn’t come at a worse time.
To be sure, Iranian support to the Taliban—both real and potential—shouldn’t be overstated. Shiite Iran isn’t about to make the Sunni Taliban its newest regional proxy, on the model of Hezbollah. The current surge of Taliban attacks in Shiite regions of Ghazni province will also prompt Iran to be cautious in its efforts to arm the Taliban. Ultimately, the deleterious consequences of a destabilizing Afghanistan—particularly refugee flows and a robust drug trade—give Tehran good reason to keep partnering with Kabul to promote stability.
Still, despite all this, even relatively modest Iranian support for the Taliban is highly problematic for a U.S. war effort that has failed to break a battlefield stalemate and rein in an insurgency that just keeps getting stronger.
Washington’s hard line on Iran also undercuts Afghanistan’s already floundering economy. If U.S. sanctions prompt Iran’s economy to tumble, Afghans working in that country could lose their jobs, eliminating their remittances and depriving cash-strapped Afghanistan of a key revenue source. Currently, about 3 million Afghans live there. An economically weakened Iran could also cause Kabul’s trade relationship with Tehran—Afghanistan’s largest commercial partner—to suffer.
Meanwhile, the chances of broader Iranian cooperation with the United States in Afghanistan are receding. This means, above all, that Tehran will not permit Washington to use Iranian territory to convey military supplies to and from Afghanistan. NATO forces currently depend on supply routes in Pakistan. If these were to be shut down—as they were in 2011 during a major spat in U.S.-Pakistan relations—Washington’s only potential alternative would be unreliable and Russia-influenced Central Asian states.
South Asia scholar C. Christine Fair has long argued that better U.S.-Iran relations could enable Tehran to play a useful role as a provider of supply routes. Earlier this year, Fair noted that Washington’s inking of the nuclear deal with Iran “opened up at least the possibility of exploring the idea of moving supplies from the port in Chabahar.” Today, however, with the bilateral relationship a mess, that small window of opportunity has slammed shut.
To its credit, Washington has softened the initial blow of its latest round of sanctions by granting exemptions that allow key Iranian commercial partners such as China and India to keep doing business with Tehran—including Indian development projects in Chabahar. Still, these exemptions aren’t meant to be permanent. And overall, the Trump administration gives no indication it is about to ease up on its tough policy. The use of force hasn’t yet been taken off the table.
For more than 17 years, America has struggled to tame the Taliban and more broadly to achieve its security and economic aims in Afghanistan. Trump’s decision to tighten the screws on Iran could make those goals even more difficult to achieve.