The path to today's problems with Iran passed through the University of Chicago squash court where on Dec. 2, 1942, for 4.5 minutes physicist Enrico Fermi, making calculations on a slide rule, achieved the controlled release of energy from an atomic nucleus. Historian Richard Rhodes says that Fermi and his colleagues were risking "a small Chernobyl in the midst of a crowded city."

Humanity was already on the path to the dangerous present in 1918 when the British physicist Ernest Rutherford, who was criticized for missing a meeting about anti-submarine warfare, said: "I have been engaged in experiments which suggest that the atom can be artificially disintegrated. If this is true, it is of far greater importance than a war."

So, when wondering about what can be done about Iran's nuclear-weapons aspirations — and North Korea's nuclear-weapons facts — remember this: Some advocates of the Iran nuclear agreement thought its purpose was to block "all of Iran's pathways to a bomb," which was Barack Obama's formulation when his goal was to dismantle the infrastructure of Iran's program.