... you have.
Instead of giving a falsely authoritative answer, you taught your son that sometimes good questions lead to imperfect answers.
Depending on his attention span (and yours), and your level of interest, you might look at what happened in Ancient Athens - where
http://en.wikipedia.org/wiki/Athenian_democracy">democracy was practiced much more openly and directly.
Your local library probably has some good books on the subject, too.
You might also throw some questions back his way (a la
http://en.wikipedia.org/wiki/Socrates">Socrates, who posed hard questions to the Athenians during the democracy's decline).
For instance, what would he predict might happen if his class officer elections were open ballots?
Or what would he predict might happen if students had to vote for their favorite teacher, with the teachers watching the vote?
; )
Once he begins to grapple with why we have secret ballots, then maybe he'll begin to ponder on how to make those ballots secure and auditable.
- Dave