On January 12, 1943, Hart was given a temporary commission of Colonel and continued in command of the II Corps Artillery. As the II Corps’ Artillery Officer he was involved with the operations of the II Corps during the drive towards Tunis, including the U.S. defeats at the Battle of Sidi Bou Zid on February 14–17, 1943 and Kasserine Pass on February 19–22, 1943. Following the Allied defeats in February, Major General Lloyd Fredendall was transferred from command of the II Corps and replaced by Major General George S. Patton on March 6, 1943.