It is easy to name leaders who successfully covered up their true face and whose incompetence and/or viciousness were fully revealed only at the pinnacle of their career. The inverse: the development when a previously incompetent, debauched or vicious leader became elevated by the obligations of the high office is so rare that only two examples: Louis XI and Duke Wellington come to mind. Sheer antiquity of these examples testify to their rareness. Louis XI turned from debauched and treacherous youth into a frugal and conscientious king, the founder of a modern French state who engineered the rebirth of the country after Hundred Years War. The winner at Waterloo Arthur Wellesley, Duke Wellington was an indifferent cadet nearly cashiered from the military.
Robert Gates belongs to this rare category. He was controversial (see Iran-Contra) Bush nominee to the directorship of CIA famous for his terrible errors of judgement. He refused to recognize ongoing collapse of USSR and gave advice not to deal with Yeltsin but also suggested to Mideastern leaders declaring "jihad" to edge Soviets from Afghanistan on the basis of "infidels occupying Moslem lands" not foreseeing that this formula can be equally applied against the USA.
Yet, his tenure as the Secretary of Defense was an unqualified success. He did not only oversaw conclusion of Iraq War and wrapping up operations of Afghanistan but also was a sane voice on American intervention into Georgia (which he acknowledges as erstwhile attackers and blames Russians for invasion of Georgia on neighboring pages) and Syria.
His memoirs accused of criticism of a sitting President whom he served are obviously a first volley in his fight for something big (Republican vice-presidential nomination or Secretary of State in the next administration). And, given the above, he might as well be successful in this new role.
