A recent Atlantic Wire article describes a study that demonstrates our society's moral decline by using the Google Books archive to track the decrease in the use of words "related to moral excellence and virtue" like character, decency, integrity, and righteousness. While I'm skeptical about putting too much stock in a word search, I agree that the dignity of American public discourse has undergone considerable decline. It's not that brilliant, morally virtuous books aren't being written today, but rather that a whole lot more junk gets published than 100 years ago. This problem has been exacerbated in the past decade with the "democratization" of discourse in social media where trolls often take over the conversation.
So what should a Christian do amidst a decaying public discourse? Too often, we Christians are part of the problem not because of the vocabulary we use but the spiritual immaturity with which we talk to people who disagree. Public discourse has come to resemble a shouting match between fans of different sports teams: the feminist team, the libertarian team, the LGBT team, the Christian team, and so forth. There seems little distinction in how each team argues its point. We delight in catching our opponents in logical inconsistency. We smack our foreheads "aloud" at how blatantly wrong the other side is. We boo at the refs when they call a foul on our team since they're so biased against us. When Christians are just another set of sports fans, then we have completely failed in our vocation.
I've come to believe that Christians' most important task in public discourse is not to argue others into agreeing with us, but to model charitable conversation. This is what I take Jesus to mean when He tells us to be "the salt of the earth." Paul says this even more directly in Colossians 4:10-11: "Be wise in the way you act toward outsiders; make the most of every opportunity.Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone." Salt exists to flavor and preserve a piece of food. It is not itself food. In the same way, the how is more important than the what when Christians speak in public. When we exude Christ in how we conduct conversation, we become part of how God creates a grace-filled public square in which Christ can be discovered. While I do believe that we have a prophetic responsibility to speak out against evil, truth-telling is so much more fruitful in the context of trusting community and covenantal discipleship. Conversations outside of the body of Christ should be focused on loving and winning the trust of others rather than making sure that they know they're wrong. How many believers come to accept Christ by getting demolished in an argument?
I found a model for the salt we need to be in the prayer that Jena Nardella delivered at the Democratic National Convention (not as a blanket endorsement but as a witness): "Give us, oh Lord, humility to listen to our sisters and brothers across the political spectrum... Equip us with moral imagination to have real discourse. Knit us, oh God, as one country even as we wrestle over the complexity of how we ought to live and govern... For we know that we are bound up in one another and have been given the tremendous opportunity to extend humanity and grace when others voice their deeply held convictions even when they differ from our own." Jesus does not win when His facebook friends outshout their opponents; Jesus wins when people taste His salt and want to feast on His love.