Overall, God.
But in a situation like this, the US Constitution. The Founders were clear - the US is meant to be Constitutional Republic(Rule of Law beginning with the US Constitution). And what is the first three words after the title of the document? 'We The People'. However we can't have 'We The People' without the US Constitution to back it up. Things that should or shouldn't be done because We The People say so but because the US Constitution states it can or can't be done.