Iran and Afghanistan

This report prepared for the Congressional Research Service, describes Iran's perceived national interests in Afghanistan:  Afghanistan: Post-War Governance, Security, and U.S. Policy by Kenneth Katzmanm 03/17/06.  Iran benefitted from the overthrow of the Taliban, as well as by the overthrow of Saddam Hussein's regime.

Katzmann writes:

Iran perceives its key national interests in Afghanistan as exerting its traditional influence over western Afghanistan, which Iran borders and was once part of the Persian empire, and to protect Afghanistan’s Shiite minority. Iranian firms are also profiting from reconstruction work in western Afghanistan, in some cases to the detriment of Afghan firms. After the fall of the Taliban in late 2001, President Bush warned Iran against meddling in Afghanistan. Partly in response to the U.S. criticism, in February 2002 Iran expelled Karzai-opponent Gulbuddin Hikmatyar, although it did not arrest him. Since then, the Bush Administration criticism of Iranian “meddling” has lessened as the pro-Iranian Northern Alliance has been marginalized in the government. For his part, Karzai has said that Iran is an important neighbor of Afghanistan. Iran did not strongly oppose Karzai’s firing of Iran ally Ismail Khan in September 2004, although Iran has opposed the subsequent U.S. use of the Shindand air base.  Iran is said to be helping Afghan law enforcement with anti-narcotics along their border. About 300,000 Afghan refugees have returned from Iran since the Taliban fell, but about 1.2 million remain, mostly integrated into Iranian society.

Even though Iran’s position in Afghanistan has waned since 2004, it is still greatly enhanced from the time of the Taliban, which Iran saw as  a threat to its interests in Afghanistan, especially after Taliban forces captured Herat (the western province that borders Iran) in September 1995. Iran subsequently drew even closer to the Northern Alliance than previously, providing its groups with fuel, funds, and ammunition, and hosting fighters loyal to Ismail Khan. In September 1998, Iranian and Taliban forces nearly came into direct conflict when Iran discovered that nine of its diplomats were killed in the course of the Taliban’s offensive in northernAfghanistan. Iran massed forces at the border and threatened military action, but the crisis cooled without a major clash, possibly out of fear that Pakistan would intervene on behalf of the Taliban. Iran has confirmed that it offered search and rescue assistance in Afghanistan during the U.S.-led war to topple the Taliban, and it also allowed U.S. humanitarian aid to the Afghan people to transit Iran.  (my emphasis)