The U. S. watched ISIS fighters, vehicles and heavy equipment gather on the outskirts of Ramadi before the group retook the city in mid - May. But the U. S. did not order airstrikes against the convoys before the battle started. It left the fighting to Iraqi troops, who ultimately abandoned their positions.U. S. intelligence and military officials told me recently, on the condition of anonymity, that the U. S. had significant intelligence about the pending ISIS offensive in Ramadi. For the U. S. military, it was an open secret even at the time. The ISIS had been contesting territory in and around Ramadi for more than a year and had spoken of the importance of recapturing the city. The U. S. intelligence community had good warning that the ISIS intended a new and bolder offensive on Ramadi because it was able to identify the convoys of heavy artillery, vehicle bombs and reinforcements through overhead imagery and eavesdropping on chatter from local ISIS commanders. It surprised no one, one U. S. intelligence official told me. Other observers were willing to speak on the record about how many had seen the ISIS ' assault on Ramadi coming. " The operations on Ramadi have been ongoing for 16 months, " said Derek Harvey, a former intelligence adviser to David Petraeus when he commanded the counterinsurgency strategy in Iraq. Harvey said many observers had seen the ISIS ' series of probing attacks and psychological operations aimed at the Iraqi army and local tribes: " Everyone knew that Ramadi for some reason was a major focus. " He conceded that he did not know the exact timing of the Ramadi offensive beforehand and acknowledged that he was surprised at how effective the operations were.Recommended:ISIS conducting systematic sexual crimes against Izadis in IraqThe Institute for the Study of War, a Washington think tank, had also been warning in policy papers that the ISIS had set its eyes on Ramadi. Kim Kagan, the think tank ' s president, told me her institute " assessed that ISIS would undertake tactical offensives in different areas of Iraq in April and May in order to disperse the Iraqi Security Forces and prevent them from consolidating their gains after the fall of Tikrit. " She said that " ISIS began alternating attacks between Anbar and the Baiji oil refinery in mid - April, " which prompted General Martin Dempsey, the chairman of the Joint Chiefs of Staff, to say in Congressional testimony that the U. S. was prioritizing the defense of Baiji over Ramadi. Kagan said the ISIS ' attack on Ramadi was not a " strategic surprise. " A spokeswoman for U. S. Central Command declined to discuss any specific intelligence. But she did say the U. S. - led coalition provided both airstrikes and surveillance to the Iraqi Security Forces in support of the Ramadi defense. The U. S. has also flown airstrikes in the past against ISIS forces in Ramadi. " Conducting air operations in heavily populated areas where ISIL hides can present challenges, " the spokeswoman, Genieve David, said. " Through our dynamic targeting process we carefully consider each target, in collaboration with our coalition partners and Iraqi forces, to ensure we do our best to minimize civilian casualties and collateral damage " But other observers said this dynamic targeting process was part of the problem. Dave Deptula, a retired general who was the first deputy chief of staff for the Air Force for intelligence, surveillance and reconnaissance, told me that airmen flying sorties in Iraq " have to call back and ask, ' mother may I ' before they can engage. " The restrictive rules of engagement for U. S. aircraft were explored this week in a devastating New York Times article that found that there are on average 15 airstrikes per day in Syria and Iraq in the new war, compared to 800 daily airstrikes in Iraq in 2003. Senator John McCain, the chairman of the Senate Armed Services Committee, last week said only one in four air missions actually result in airstrikes in the current war. " If the administration is only going to use airstrikes, they are going to have expand what constitutes a target, " Representative Devin Nunes, the chairman of the House Permanent Select Committee on Intelligence, told me. " I have been concerned for a long time that the limited number of targets would ultimately lead to the fall of many cities in Iraq. This didn ' t come as any surprise to me that Ramadi fell. " Deptula agreed. " The current rules of engagement are intentionally designed to restrict the effectiveness of air power to prevent potential collateral damage, " he told me. " That results in ISIS getting the freedom of action so they can commit genocide against civilians. Does this make any sense? " To be sure, the rules of engagement for U. S. airstrikes were not the only setback in the battle for Ramadi. The Iraqi military withdrew from its positions in the city. This prompted Defense Secretary Ash Carter over the weekend to tell CNN that the U. S. was surprised the Iraqis lacked the will to fight. But the forces deployed in Ramadi also were not properly resupplied, according to U. S. military and intelligence officials. Harvey, the former Petraeus adviser, told me that " since September, Iraqi forces deployed to Anbar have had to purchase some weapons and ammunition on the black market because supplies are not getting to them. " Another problem in the battle was that although the U. S. special operations forces have been training Iraqi troops since the summer in bases, they are still not authorized to accompany the Iraqis into battle. This is standard procedure in Afghanistan and other theaters where the U. S. trains security forces. " I am hearing a lot within the special operations community that we are leaving options on the table and not employing lower - risk capabilities that would make a difference, " Harvey told me. Harvey added that these low - risk options included using U. S. personnel on the ground to select targets for airstrikes, conducting special operations raids on ISIS targets in Iraq and embedding special operations forces with the Iraqi units they were training. Harvey contrasted this approach to the surge in 2007 and 2008, when U. S. soldiers patrolled Iraqi cities and engaged in direct combat with al Qaeda and other insurgent groups. It ' s not clear whether Harvey ' s recommendations would violate President Obama ' s own red lines against authorizing ground combat operations in Iraq. What is clear is that while the U. S. is holding back from those measures nearly a year into Obama ' s new Iraq war, the ISIS has been able to hold Iraq ' s second - largest city, Mosul, and has just taken the strategically important city of Ramadi.By Eli Lake First published in Bloomberg View