Following the Battle of Đồng Xoài in June 1965, when the 5th Division 1st Battalion, 7th Infantry Regiment was ambushed by Viet Cong forces in the Thuận Lợi rubber plantation suffering heavy losses, the Division's US adviser reported that Thuần, had "gone to pieces" over the mauling his 7th Regiment had received.
Although assessed by American leaders as corrupt and incapable, Thuần had strong political ties with the Junta generals, particularly Thiệu.
John Paul Vann noted the widespread public belief that Thuần controlled most of the local bars and prostitution houses and extorted protection fees for convoys moving through his Division tactical area.
The division, together with General Du Quoc Dong's airborne units, remained Thiệu's major power center.
Minor incidents, like Thuần's daily pot shots at birds from the second story balcony of his home and the subsequent accidental wounding of his intelligence adviser, were not uncommon and at times trivialized and mocked the entire war effort.