Since the early to mid-1990s, Iranian policy in Afghanistan has been more consistently and firmly opposed to the Taliban than that of the United States.
The Obama administration thus appears to be pressing that charge as a means of increasing political-diplomatic pressure on Iran over its nuclear program, despite NATO’s need for Iranian help on Afghanistan.
United States Central Command chief General David Petraeus declared in testimony before the Senate Armed Services Committee on April 1, “In Afghanistan, Iran appears to have hedged its longstanding public support for the [President Hamid] Karzai government by providing opportunistic support to the Taliban.”