The WSJ's Neil King Jr. and Greg Jaffe have a great feature (available for free here) on the geo-political implications and reprecussions of the US-led Iraq 'strategy' change.
We've been antagonistic toward Iran for almost thirty years now. We withheld support for Massoud's Northern Alliance in Afghanistan for too long as the Taliban grew in the country's south, in part because of Massoud's friendly ties to Iran.
Despite pincering Persia through US-led invasions to the country's east and west, this paltry place is causing us all kinds of headaches. And as the WSJ details, the big winner of the Iraq--historically hostile to its eastern neighbor--debacle is none other than our putative arch-nemesis in the region, Iran. Despite the WSJ op/ed's paeans celebrating open borders in North America, Jordan is mobilizing forces to shut down the influx of Iraqi refugees pouring into her capital, Egypt is considering sending equipment and munitions to Sunni fighters in Iraq, and the Saudis are looking (and have probably already begun) to funnel cash to the Baathist remnants in a desperate attempt to quell expanding Iranian influence in the Persian Gulf.
History may well show the Iraq invasion to be the worst tactical blunder in all of America's storied history.