Power always Sincerely, conscientiously, de très bon Foi, believes itself Right. Power always thinks it has a great Soul and vast Views, beyond the Comprehension of the Weak; and that it is doing God Service when it is violating all his Laws.

John Adams (1735–1826) American lawyer, Founding Father, statesman, US President (1797–1801)

Letter (1816-02-02) to Thomas Jefferson
    (Source)

De très bon foi = "very candidly."