Christopher Bellamy: How the resistance movement caught Allies in a trap

As the Battle for Baghdad gets under way, the Iraqi defensive strategy is looking increasingly sound. In his speech yesterday, Saddam Hussein said the invaders were "trapped" by heroic Iraqi resistance. In a way, he may just be right.

The pace of the US 3rd Mechanised Infantry Division's race up the Euphrates and towards Baghdad has been almost unprecedented in the history of war. But as this mighty armoured force heads for the capital, its main supply route looks increasingly vulnerable. The Iraqis have let the Americans, and, to a lesser extent, the British, roll over them and then appeared behind the invaders in small groups to harry them from the rear.

The US and British formations pressing towards Baghdad and held on the Euphrates and Tigris have had to "reconsolidate", and go into all-round defensive positions to guard against opposition coalescing behind them. In that sense they are, as President Saddam put it, "trapped".

The left flank of the Allied thrust has gone extremely fast; the right, far more slowly. The Iraqis have therefore achieved exactly what they need: they have identified the main enemy thrust. The Iraqi generals, including quite a few trained at Sandhurst, know what to do next. Counter-attack the isolated spearhead with a massive armoured reserve. Of the Republican Guard Force's six divisions – the only Iraqi divisions to be at full strength – three are in the area around Baghdad. A full-scale armoured battle is probably what the US planners want, because they would win it. The Iraqi generals know full well what happens when T-72s and BMPs come up against M1 Abrams and Bradleys, Apaches and A-10 Thunderbolts. That is why, so far, the Iraqi strategy of avoiding large-scale battle has been so successful. But the appearance of the Americans, tired and at the end of their supply lines, outside Baghdad might be too great a temptation. The resulting contest could be symbolic, with shades of the Battle of Kursk in 1943.

The Allied attack, indeed, has much in common strategically with the German assault on Soviet Russia in 1941 and, from an operational viewpoint, with the invasion of France in 1940. In the former, the Germans, neglecting their flanks, tore across Belgium and northern France to the sea in a few days. Guderian's crossing of the Meuse at Sedan is considered to be the master-stroke which made this possible, and it is no coincidence that, before the present war broke out, US armoured divisions were instructed to study it. By a strange coincidence, the crossing over the Euphrates at Nasiriyah is much the same distance from Baghdad as Sedan is from Paris. In 1940, the British and French attempted to cut the advancing German spearhead off with a counter-attack from north and south. In fact, only the British attack, at Arras, had any chance of success. It failed, partly because they lacked air support, but gave the Germans, including Rommel, a real shock. The US commanders are no doubt confident that their overwhelming air superiority and the complete "transparency of the battlespace" will mean they can identify and destroy any Iraqi counter-attacks.

The comparisons with 1940 are ultimately comforting to the American and British forces. Those with 1941 are less so. As they fanned out into the vast spaces of the western Soviet Union, the Germans encircled vast numbers of Soviet troops. But many of the troops were able to work their way out, and others, left behind by the swift German advance, joined local people to form partisan units. That is exactly what seems to be happening in southern Iraq at the moment.

The Allied commanders must be worried at this continued resistance around and behind their advanced forces. They could deal with it, if they were more brutal in their use of the available weaponry or if they had more troops. If such resistance continues it will be necessary to deploy more troops, either regulars or reservists, or to use Iraqi units which have come over to the Allies for rear-area security.

At the moment, the latter looks a very risky option. The forward formation – the 3rd Infantry Division – also faces problems. The troops are all very tired. It seems inconceivable that they will be committed to assaulting Baghdad itself. Baghdad is a city with a million more people than Rome. The idea of Allied troops getting involved in street fighting is terrible to contemplate. It is most likely that, having reached the edge of Baghdad, it will have to halt for resupply and for other formations to catch up. This may be the significance of the capture of the H2 and H3 airfields west of Baghdad, which could be used as jumping-off points for airborne and air-landed forces.

Sunday night saw the heaviest bombing of Baghdad so far, although the media concentrated, understandably, on the capture of US troops. Reporters in the city told of the biggest explosions they had heard so far, suggesting the Americans may have started using the formidable Massive Ordnance Air Burst (MOAB) weapon, which is as powerful as 20 to 30 tons of Second World War RDX and makes a cloud looking like a nuclear weapon. The new military jargon is "Effects-based warfare" – the use of military power for political effect. There has been continued and stiffening Iraqi resistance. The US has been humiliated. Not only have the Iraqis been putting up a decent fight, but they have taken American prisoners. Still heavier assaults on Baghdad can therefore be expected.

Christopher Bellamy is professor of military science and doctrine at Cranfield University.