WASHINGTON (AP) — U.S. teams of special forces going into Iraq after a three-year gap will face an aggressive insurgency, a splintering military, and a precarious political situation as they help Iraqi security forces improve their ability to battle Sunni militants.The Army Green Berets, expected to make up much of the U.S. force, have been assessing and training other militaries for decades as a core part of their job. But while much of what they will be doing in Iraq will be familiar, it will be complicated by the stunning collapse of the Iraqi military, left leaderless by internal Sunni-Shiite divisions.Experts suggest that while the elite commandos may be able to stop the immediate deterioration of Iraqi forces, it will require a far broader effort to quell the deep sectarian divide in the country and put systems in place to build more professional military leadership.The U.S. and Iraq on Monday reached a key agreement on legal protections that will enable up to 300 special operations forces to deploy in the country. Two teams of 12 members each are already in Iraq and could begin their assessment this week, and another four teams are expected to go into the country soon."They will be very good at improving the immediate tactical proficiency of some of the Iraqi military, but they will be less prepared to address the long-term health of the Iraqi army," said retired Lt. Gen. James Dubik, who was in charge of training Iraqi forces in 2007 and 2008.