Iran is likely to face renewed challenges in Afghanistan, where militants are expected to launch their annual spring offensive. While much focus is on the issues the Islamic republic faces to its west, in Iraq and Syria, the challenges to its east may well prove to be at least equally vexing for Tehran.

Over the last 15 years, the Afghan situation has epitomized the ups and downs Iran has experienced in its relations with its Arab rivals and the United States. 

After 9/11, Iranian-US contention over Afghanistan turned into cooperation, with the aim of ousting the Taliban. For the United States, the Taliban had to be removed as it sheltered al-Qaeda. For Iran, the regime in Kandahar constituted a genuine security threat; in 1998, following the killing of Iranian diplomats in Mazar-i-Sharif, Iran and Taliban forces were on the verge of all-out war.

Shared goals provided impetus for crucial Iranian-US intelligence and security cooperation. Senior Iranian sources confirm to Al-Monitor that Tehran even offered two airfields on its border with Afghanistan for use by US transport aircraft. Perhaps more importantly, Iran facilitated coordination between its Afghan allies and Washington, and played a vital role in the establishment of a new Afghan government. Current Iranian Foreign Minister Mohammad Javad Zarif is widely credited with the latter.