 South Vietnamese forces had performed well during the incursion but their leadership was uneven . General Tri proved a resourceful and inspiring commander , earning the sobriquet the " Patton of the Parrot 's Beak " from the American media . General Abrams also praised the skill of General Nguyen Viet Thanh , commander of IV Corps and <unk> of the Parrot 's Beak operation . Unfortunately for the anti @-@ communists , both officers were killed in helicopter crashes — Thanh on 2 May in Cambodia and Tri in February 1971 . Other ARVN commanders , however , had not performed well . Even at this late date in the conflict , the appointment of ARVN general officers was prompted by political loyalty rather than professional competence . As a test of Vietnamization , the incursion was praised by American generals and politicians alike , but the Vietnamese had not really performed alone . The participation of U.S. ground and air forces had precluded any such claim . When called on to conduct solo offensive operations during the incursion into Laos ( Operation <unk> Son <unk> ) in 1971 , the ARVN 's continued weaknesses would become all too apparent . 
