Justice, truth and peace

In this week's perek of Pirkei Avos, we read that the world exists because of three things--justice, truth and peace.
Well, two out of three ain't bad.
Justice is a no-brainer.  Without justice, we ride roughshod over each other.  But truth and peace?  Can those two ever co-exist?
As I've said before, the cardinal sin an any friendship is a completely honest answer.  Sometimes the truth is ugly.  Sometimes it hurts.  Sometimes being honest can even cause rifts that end a friendship.
But is peace the better alternative?  Sometimes those ugly truths need to be spoken.  Sometimes the fight is worth it for the sake of a better outcome.
And I think that's where the justice comes in.  Without justice, truth and peace cannot coexist.  Justice helps us balance out these two opposites.  If one is a just person, with a good moral code, one will know the correct time for truth, and the correct time for peace.