Here's the thing.
If you believe that you are a good person, you can justify anything because you're a good person, and want to do the right thing.
Reagan was head of the Screen Actors Guild, and spied on his own members for the FBI. If you asked him he would have told you it was for a good reason; they had to stop the Evil Empire.
If there were problems with any of his polices, it was a temporary thing, and what was good for the majority of people outweighed anything bad that happened.
If you are actually trying to do good, or if you're actually intelligent, you always second guess yourself.
If you believe that you're good, or smart, you never have to waste your time thinking about that stuff.