Editing Battle of Monte Cassino (section)

===Main attack: II Corps in the centre, 20 January===
{{Further|Battle of Rapido River}}
[[File:Bundesarchiv Bild 101I-312-0998-27, Monte Cassino, Panzerreparatur während Kampf.jpg|thumb|right|A German tank crew attempts to restore their [[Panzer IV]]'s mobility after battle damage inflicted during the fighting]]

The central thrust by the U.S. 36th Division, under Major General [[Fred L. Walker]], commenced three hours after sunset on 20 January. The lack of time to prepare meant that the approach to the river was still hazardous due to uncleared mines and booby traps, and the highly technical business of an opposed river crossing lacked the necessary planning and rehearsal. Although a battalion of the [[143rd Infantry Regiment (United States)|143rd Infantry Regiment]] was able to get across the Gari on the south side of San Angelo and two companies of the [[141st Infantry Regiment (United States)|141st Infantry Regiment]] on the north side, they were isolated for most of the time and at no time was Allied armour able to get across the river, leaving them highly vulnerable to counter-attacking tanks and self-propelled guns of ''[[Generalleutnant]]'' [[Eberhard Rodt]]'s [[15th Panzergrenadier Division (Wehrmacht)|15th Panzergrenadier Division]]. The southern group was forced back across the river by mid-morning of 21 January. Keyes pressed Walker to renew the attack immediately. Once again, the two regiments attacked but with no more success against the well dug-in 15th Panzergrenadier Division: the 143rd Infantry Regiment got the equivalent of two battalions across, but, once again, there was no armoured support, and they were devastated when daylight came the next day. The 141st Infantry Regiment also crossed in two battalion strength and, despite the lack of armoured support, managed to advance {{convert|1|km|mi}}. However, with the coming of daylight, they too were cut down and by the evening of 22 January, the 141st Infantry Regiment had virtually ceased to exist; only 40 men made it back to the Allied lines.

[[Rick Atkinson]] described the intense German resistance:

{{blockquote | [[Artillery]] and [[Nebelwerfer]] drumfire methodically searched both [[bridgehead]]s, while [[machine gun]]s opened on every sound&nbsp;... [[G.I. (military)|GIs]] inched forward, feeling for trip wires and listening to German gun crews reload&nbsp;... to stand or even to kneel was to die&nbsp;... On average, soldiers wounded on the Rapido received "definitive treatment" nine hours and forty-one minutes after they were hit, a medical study later found&nbsp;..."{{sfn|Atkinson|2007|pp=344–354}}}}

The assault had been a costly failure, with the 36th Division losing 2,100<ref>E.D. Smith, p. 59.</ref> men killed, wounded and missing in 48 hours. As a result, the army's conduct of this battle became the subject of a [[Congressional inquiry]] after the war.