However, South Vietnamese officers were often reluctant to absorb heavy casualties. On several occasions, Cao's forces were in an excellent position to trap and wipe out whole battalions of VC, but he would fail to close the trap on one pretext or another and allow the enemy to escape. This behavior initially mystified Vann, who was attempting to build Cao into an aggressive commander. Unknown to Vann, Diem would reprimand or demote any officer who lost too many men, no matter how successful the operation. Diem was more interested in using the military to protect his regime than to take on the VC. His solution was to fill the ARVN with Catholic political cronies and friends like Cao, Lê Quang Tung, and Tôn Thất Đính, who had little military ability, but were very likely to help stop a coup attempt. After a skirmish on a highway that resulted in a small number of South Vietnamese casualties along with several trucks destroyed, Cao was called to Saigon and reprimanded by Diem. Upon his return, Vann and his group of advisers were forced to end the joint planning sessions that had been so successful earlier, and action essentially wound down in their region. Cao used the excellent military intelligence network they had developed to find areas devoid of VC, and planned operations only in those areas. In many other cases, operations were executed on paper only, in order to report an increasing tempo of operations that did not actually exist.