In the horrific shadow of a past nuclear holocaust, the leaders of the G7 group of wealthiest nations will meet in Hiroshima Japan this weekend to discuss war; how to prosecute one in Ukraine and how to prevent one with China. Jake Sullivan, the US national security adviser, once described the G7 as the coordinating committee of the free world, and never has there been such a need for such coordination. It was only in October that Joe Biden warned the risk of a nuclear Armageddon was at its highest in sixty years. Since then the chance of Vladimir Putin...