We once had faith in persuasion through debate and discussion. We hoped that by making our ideas clear, others would see that we were right. Sometimes we even changed our minds when our opponents raised points we could not refute. Not everybody was open to dialogue; we have never lacked for stubborn people or ideologues. But those traits were generally seen as flaws, not as something to be emulated.

Today slogans have taken the place of arguments. The point of discourse has increasingly shifted from explanation to affiliation. We preach to the choir, and they sing back to us. Converts are neither sought nor desired. Our hashtags, slogans, and memes function less as arguments than as markers of tribal membership.