Any clash between the US and Iran as a regional power can have grave consequences for Afghanistan. Tehran also currently accused of supporting the Taliban can create a lot of challenges for Afghanistan in addition to increasing its support to Afghan militants if US-Iranian ties get further strained.
While Afghanistan’s relations with its eastern neighbor, Pakistan, are also tense, Iran is the only option for Afghanistan through which it can maintain its economic relations with other states. Any strain in Afghan-Iranian ties for the sake of the United States can pose major security challenges to the country besides having serious repercussions for Afghan economy. If Kabul downgrades its relations with Tehran to attract US support, or for whatever other reasons, it will intentionally open another front of proxy wars in the war-battered country.
Heightened US-Iran tension will further toughen the job for the embattled Afghan government, thus Afghanistan should maintain a balance in relations with its major military ally, and a country mostly considered an alternative for Pakistan in terms of transit. It is difficult, but not impossible. The government should try to expand relations with both sides, and not allow any of them to sacrifice Afghanistan for their interests. Through active diplomacy, Kabul should make Washington and Tehran understand that the time has gone to use Afghanistan as a battlefield of proxy wars, and that Afghans, as President Ghani says, want their country to serve as a ground of cooperation than competition for other countries.