Not only did the Sicily operation represent a watershed in tactical development of combined arms tactics, it was also an important test for future Allied joint operations. Senior British commanders left the North African theatre with a jaundiced and dismissive view of the combat capabilities of the inexperienced US Army after the debacle at Kasserine Pass in Tunisia in February 1943. Sicily was a demonstration that the US Army had rapidly learned its lessons and was now capable of fighting as a co-equal of the British Army.