what does the story say about how well the justice system functions?

Twelve Angry Men is in many ways a love letter to the American legal justice system. We find here eleven men, swayed to conclusions by prejudices, past experience, and short-sightedness, challenged by one man who holds himself and his peers to a higher standard of justice, demanding that this marginalized member of society be given his due process. We see the jurors struggle between the two, seemingly conflicting, purposes of a jury, to punish the guilty and to protect the innocent. It proves, however, that the logic of the American trial-by-jury system does work.