Aligning our duties with our interests

From Rousseau’s Confessions:

“They [Rousseau’s reflections on what he’d learned of ethics] have taught me one great maxim of morality, the only perhaps which is of practical use: to avoid situations which place our duties in opposition to our interests, and show us where another man’s loss spells profit to us. For I am sure that, in such situations, however sincere and virtuous the motives we start with, sooner or later and unconsciously we weaken, and become wicked and unjust in practice, though still remaining good and just in our hearts.”

How true. I think this applies to government more than anywhere else.