The rapid advance of American ground forces northwards has been slowing down for the last couple of days, and it appears that it has been decided to halt further advance so that forces can regroup and secure the supply lines. Some of the US observers have described the present position as the failure of Pentagon strategy.All armoured-mechanised forces require huge quantities of fuel, ammunition and food supplies across large distances. The logistic lines of supply of US Army are now stretched out across Central Iraq with the main starting point nearly 350 km to the south. In between are towns and cities from where highly motivated guerrilla forces sally out to battle the Americans and place its supply lines at great risk. Americans now must try and get rid of the threat to their extended supply lines, wait for reinforcements, and try and weaken the Iraqi Army by extensive use of air power in the areas more immediately ahead of its forces than keep rushing headlong to Baghdad.Militarily, the change in plans of US ground forces makes sense even if it was not expected. But its political and psychological consequences could be crucial in the coming days and weeks. At the minimum, this would bolster the fighting spirit of Iraqi forces, while shoring up the morale of the civilian population.As it is, there has been no sign of the population welcoming the Anglo-American forces as liberators. The invasion in reality has strengthened Saddam both inside Iraq and around the Arab world.Any slowing down of the US military operation would generate its own dynamics, both inside Iraq as well as across the world. For example, instead of the expected revolts, Shia leaders like Sheikh Mohamed al-Khakani, the top Imam in Najaf, two days ago called for jehad by ‘‘expelling the unbelievers from the land of Islam’’ while Iran-based leader of the main armed Opposition group of the Iraqi Shi’ites, Ayatollah Mohamed Bakr al-Hakim, warned allied forces to leave Iraq or face military resistance.The rapid advance of light forces which was to take the armour columns to the outskirts of Baghdad was first slowed down by the extensive duststorms and then by the stiff resistance from irregular forces.As Lt. Gen William Wallace, US commander of the land forces in Iraq, remarked: ‘‘This enemy is different from the one we war-gamed.’’ As a consequence, the strategy to advance along the main road axis from Kuwait to Baghdad with numerous cities and towns along the line held by hostile forces proved to be highly risky since it increased the vulnerability of the supply lines with inadequate forces to secure them.This probably prompted Saddam to move a Republic Guard Division forward from Baghdad under cover of the storm to the Karbala Gap. It is, therefore, extremely important for the US forces to be reinforced and secure supply lines. Nearly 30,000 troops are expected to come in within the next week, while another 120,000 would be inducted during the coming four weeks.Between the two choices that the US now has, the one to wait for reinforcements while consolidating defensive position, reduce the militia fighters’ capabilities to interfere, and use air power to whittle down the Iraqi forces is the most logical and less risky. Meanwhile, actual combat would continue with the use of air power.Air Commodore (retd) Jasjit Singh, editorial consultant to The Indian Express, will analyse the war daily. Readers can send their queries to him at jasjitsingh@expressindia.com