text: will iran overrun iraq once the u.s. leaves?   already the shias are looking upto iran for guidence. the us presence in iraq is strenthening the iranian influence in this region. dont be supprised if the main shias break away and join iran. it is in the interest of iran to expand there territory. the us has achieved exactly the opposite effect of what they set out to do. they are actually handing over iraq to the iranians on a silver plate and there is very little they can do, to totally avert this. this is probably the main reason that us does not want to withdraw its troops quickly.