If you drive the southern route between Frankfort, the capital of Kentucky, and Oklahoma City, Oklahoma, your halfway point will be Memphis, Tennessee. The route forms an arc, a shape on the minds of many on this 50th anniversary of the assassination of Martin Luther King Jr. Paraphrasing the abolitionist Theodore Parker, Dr. King famously said, “The arc of the moral universe is long, but it bends toward justice.” King was gunned down on April 4, 1968, while supporting striking sanitation workers in Memphis. Half a century later, thousands of teachers are on strike from Kentucky to Oklahoma. The night before he was killed, Dr. King gave one of his best-known, most prophetic speeches. He declared, “I have been to the mountaintop,” but earlier in the speech, King, an ardent union activist, spoke to the striking sanitation workers he was in Memphis to support: “Whenever you are engaged in work that serves humanity and is for the building of humanity, it has dignity, and it has worth. You are reminding not only Memphis, but you are reminding the nation, that it is a crime for people to live in this rich nation and receive starvation wages.”