"If they have evidence," Abedin says of the U.S. military, "they've certainly not made it public."
Not everyone is convinced Iran's role in Iraq is as direct as U.S. officials suggest. Mahan Abedin, director of research for the London-based Center for the Study of Terrorism, told RFE/RL that allegations of a direct link between the Quds Force and dead American soldiers are "essentially political." "If they have evidence," Abedin says of the U.S. military, "they've certainly not made it public." Gen. Bergner, speaking with reporters in September 2007 to announce the capture of suspected weapons smuggler Mahmudi Farhadi, declined to discuss evidence.

Others question what sanctions against the Revolutionary Guards or its foreign counterparts would accomplish. The U.S. State Department has included Iran on its list of state sponsors of terrorism since 1984. But efforts to slap sanctions on the country's military forces could prove problematic, some analysts predict. Writing in the Financial Times, CFR's Takeyh says proposed sanctions illustrate the Bush administration's misunderstanding of Iranian politics. "At a time when the administration professes a desire for a negotiated settlement with Tehran," Takeyh concludes, "coercing a pillar of the theocratic regime erodes the possibility of a diplomatic resolution." Reidel is equally skeptical. "We're not going to put them out of business." Yet others say the move is long overdue. Because the unit's financial holdings bleed so far into the Iranian economy, Sazegara predicts sanctions on the Revolutionary Guards "would be fairly effective on Iran as well."