It is very hard to discuss justice without referring to contemporary politics and therefore causing more harm in lost friendships than good that comes from discussing issues. I want to continue to hold back from jumping into today's headlines as much as possible, but while I am thinking about it I wanted to post this as a topic that might be discussable because the heat of the moment has now passed by 2000 years.
I'm referring to Cicero's conundrum in dealing with the conflict between (1) his professed allegiance to ideal unchanging justice (here, in the form of the Roman Sempronian law that Roman citizens not be executed - or is it executed without trial?) and (2) his conviction that if he did not execute the Cataline conspirators quickly, the Cataline Conspiracy would win, he and much of the Senate would be killed, and the Roman Republic and with it the Sempronian law would be destroyed. If anything should have convinced Cicero that there is in fact no absolute justice, this situation should have done it! But in fact I gather this conflict apparently had no influence in lightening up Cicero's view of Epicuruean justice.
Here is a link to a blog that discusses the issue facing Cicero, but I am afraid it does a poor job of covering the philosophical issue of justice. I remember reading much more detail back when I was studying Cicero much more closely, and this is a topic that has been debated for 2000 years so there is much better stuff out there.
If we need an example for debating the limits of "rule of law," this is probably a good one, and I doubt too many people will lose friendships over it 
https://thecatilineconspiracy.wordpress.com/2013/04/22/the…ian-executions/