Hi D&O,
I think the broad aim is to increase happiness and/or avoid harm for the most people possible.
If that can be done by some sort of popular mandate, that is great.
But your brother is right. The local culture and the social infrastructure may not bear the freight.
For myself, I am historically conservative in the way I imagine societies finding a constructive path forwards. Mostly it is going to be done internally and gradually based on existing methods.
Outside interference isn't going to work unless a society embraces wholesale change.
Saddam was awful. But was he worse than what is left behind by American intervention?
If only Bush had focused only on Afghanistan.