The senior American commander in Iraq has provided unusually detailed information supporting suspicions that Iran is helping the insurgency in Iraq as a matter of official government policy. Iran is providing weapons, technology for explosive devices and training, according to General George Casey. He said roadside bombs that explode in one direction are known to be manufactured in Iran. The strong possibility that the Iranian government is orchestrating a surrogate war on behalf of radical Shiite elements in Iraq adds to the urgency of diplomatic efforts to curtail Iran's nuclear weapons program. It also alters the variables the U.S. has to consider in the Iraq conflict. Iran once enjoyed a dominant position in the Middle East, and its current leadership entertains notions of recovering that influence. Iran's quest to join the nuclear powers supports that ambition. Supporting the insurgency and attempting to manipulate Iraqi politics is a logical extension of the same policy, and this is a dangerous proposition for the U.S. In addition to Al Qaida, supporters of the former regime, religious factions in Iraq, jihadists from other Arab countries, it must deal with a powerful terrorist patron next door. The danger underscores the importance of reaching out to friendly factions in Iran. For if that effort fails, Iran will become a much greater threat to world security, and the stakes in Iraq will be much higher and more costly than they are now.