Yesterday's crossing of a line by a presidential candidate, as egregious as it was, is symptomatic of a pervasive malady afflicting the American church as well as its cultural context: credence in the "myth of redemptive violence" (Walter Wink's coinage). It's time to declare the renunciation of all forms of violence and the embrace of the nonviolent way of Jesus a matter of status confessionis for the church (a state of affairs in which the fundamental essence of the Gospel the church confesses is at stake).
This will include forsaking the Niebuhrian realism that has been the received ecclesial justification for American foreign policy since the 1950s, in the Cold War and in the "war on terror." Its pervasive influence was evidenced in the 2008 presidential election campaigns, with both John McCain and Barak Obama crediting Niebuhr's influence on their political philosophies. It can be argued that Niebuhrian realism, offered to the polis by the church, undergirded both the invasion of Iraq under President Bush and the escalation of drone strikes under President Obama (I assert this as someone who voted enthusiastically for Obama twice and continues to admire him and his presidency).
All this is to say that as the church we must both denounce what happened yesterday in Wilmington, North Carolina, and repent of our complicity in the formation of a culture in which those words actually strike a chord with some Americans, so that as followers of Jesus Christ we might actively live into the shalom of the reign of God.