Donald Trump’s menacing threat to Iran that “A whole civilisation will die tonight, never to be brought back again” has unintentionally brought to light Rajiv Gandhi’s genius in anticipating that India and Pakistan might do just this to each other unless protected from such an eventuality in times of tension and war.

After the unspeakable horrors of World War II, the international community decided to newly codify humanitarian law through four conventions adopted in August 1949 in Geneva, including the fourth relating to the “protection of civilian persons in time of war,” because casualties were no longer confined to combatants on battlefields.…