Poetic to the core, King used religion express a desire for the common good. While I prefer religion not be included in political appeals there is a way to do it that is helpful. King knew how.
Today, the most common way today to link God to politics is to say, “The United States is God’s favorite nation. It was founded by Christians on Christian principles. My party (or me as a candidate) pledge to carry our God’s will….”, While King may also have said this kind of thing in his thousands of speeches, his more overarching expression related to politics was, “We are tied together in the single garment of destiny, caught in an inescapable network of mutuality. Whatever affect one directly affects all indirectly. For some strange reason I can never be what I ought to be until you are what you ought to be..This is the way God’s universe is made.”
Variations on this have been stated thousands of times by preachers and politicians. Donald Trump did not say it. He seems to have given up trying to quote scripture or express religious ideas. I didn’t watch his acceptance speech but I’ve not heard he used the term “common good.”
I heard Hillary talk in person recently and she touched on themes of the common good without attributing it to God as King did. I’m guessing we will hear some about God at the Democratic Convention.
Most of it will come from her running mate.