MOSUL – The tactical assembly area for US forces south of Mosul is as nondescript as could possibly be. In a nearby field the M109 Paladin howitzers – mobile artillery that drives around on tank treads – nestle amid earthen berms. Their supply vehicles are dug in behind them. The field is full of mud, odd for northern Iraq, but it had been raining a lot in late March.Lt. Micah Thompson, a platoon leader, says “we have the capability to address all targets; the point of the Paladin is a mobile artillery system. The fight that we bring is the precision munition capability. We are able to program and set those fuses and provide those rounds downrange in rapid time in order to accomplish [our task].” He’s one of the recent generation of US Army soldiers serving in Iraq, and he’s enthusiastic about providing fire support to the Iraqi security personnel who are slowly clearing Mosul of Islamic State fighters.Behind the muddy field, the rest of the quiet US Army base goes about its business in close proximity with the Iraqi Federal Police and Emergency Response Division, two Iraqi units leading the battle for Mosul. This is the tip of America’s spear in the battle against ISIS, but in contrast to previous US campaigns in Iraq, the Americans are letting the Iraqis set the tempo. Lt.-Col. John Hawbaker, a commander in the 73rd Cavalry Regiment of the 82nd Airborne Division, joined the army in 1998 and served in Iraq in 2005-2006. He says ISIS represents the “same barbarism, evil and cruelty” that the US faced back then, but is “a much larger and conventional threat. We were doing counter-insurgency with US leadership, the difference now is the Iraqi Security Forces conduct a fight not as a counter-insurgency but against a conventional force.”This is a key difference in the US outlook. In 2006, Gen. David Petreaus played a role in crafting a US field manual on Counterinsurgency, later referred to as COIN, or counter-insurgency strategy.In those days the US Army was dealing with a “comprehensive civilian and military effort taken to simultaneously defeat and contain insurgency and address its root causes,” as the FM 3-24 Insurgencies and Countering Insurgencies manual of May 2014 described it. H.R McMaster, now the national security adviser, but then a colonel, trained his regiment to deal with manning checkpoints and treating Iraqi civilians with dignity, to prepare to fight in Tal Afar, northwest of Mosul. George Packer in a 2006 piece in The New Yorker described not only how McMaster led Iraqis in rooting out insurgents, but how “Americans are not just training an Iraqi Army, they are trying to build an institution of national unity.”Ten years later, the US has given up some of these grandiose pretensions, with a much smaller footprint on the ground and a reduced visible presence. US Army vehicles I saw don’t fly the US flag and the only way you know they are US vehicles, according to one local Iraqi, was that they use old MRAPs (Mine Resistant, Ambush Protected vehicles). “We have multiple ways we assist,” says Hawbaker. “You saw the artillery in direct fire, mortars, and we also help coordinate air strikes, and we also help coordinate intelligence sharing, so we give them a lot of info on disposition and what he [ISIS] is doing and what he [ISIS] is thinking and intelligence for them to better array their operations.”Everything is focused on aiding the Iraqis, not leading them. This is termed 'advise and assist.' The Iraqi Army sets the tempo and the goals, and the US advises. For instance, on April 12, the Department of Defense noted that the US carried out eight air strikes in Iraq, hitting vehicles, mortars, snipers, and bomb factories.Although training of the Iraqi forces and Kurdish Peshmerga is a major part of the operation, the overall narrative has changed; the US is more humble and modest in its approach than a decade ago. Instead of trying to rebuild the Iraqi Army as an institution – which the US was struggling with in the wake of the 2003 invasion when the army was disbanded and competent, but Ba’athist officers were sent packing – the US continually stresses that it “supports” the Iraqi Army.This has allowed Iraq to take ownership of the war, and to make the mistakes and climb the learning curve that inevitably results in their soldiers improving. This strategy has been effective at fighting ISIS over the last two years, but it has also been slow. The battle for Mosul has taken six months, and will likely take more, even as question marks are raised about what comes next in ISIS-held Tal Afar, Hawija, and parts of Sinjar and Anbar.