<P> On February 19 , 1965 , some units of the Army of the Republic of Vietnam commanded by General Lâm Văn Phát and Colonel Phạm Ngọc Thảo launched a coup against General Nguyễn Khánh , the head of South Vietnam 's ruling military junta . Their aim was to install General Trần Thiện Khiêm , a Khánh rival who had been sent to Washington D.C. as Ambassador to the United States to prevent him from seizing power . The attempted coup reached a stalemate , and although the trio did not take power , a group of officers led by General Nguyễn Chánh Thi and Air Marshal Nguyễn Cao Kỳ , and hostile to both the plot and to Khánh himself , were able to force a leadership change and take control themselves with the support of American officials , who had lost confidence in Khánh . </P>
why did the us support several coups in south vietnam during the 1960s
had lost confidence in Khánh