The next horror wasn't long in coming. Dallas, St. Paul, and Baton Rouge, all within just over a day.
Taken together, what happened in rapid succession in these three distant locations may have the greatest impact on the country, its direction, and the upcoming elections.
There is polarization on basic economic policy and also, potentially, on crucial matters of war and peace. But the future may well turn on the storm over systemic racism and violence. Race hatred, jingoism and xenophobia are what Trump counts on to inflame vigilantes in the name of "law and order". Racism is the fault line on which he hopes to stage an upset win in November.
The conscience of many Americans has been shaken by heart-searing videos and by the rising cry that Black Lives Matter. Will the appeal of justice and reason be strong enough to prevent escalation of the violence into a full-blown war? Can it force a halt to the killings? Can it bring about a massive rejection of Trump and Trumpism?