The Earth is getting hotter. How heat domes, El Niño and greenhouse gases all play a part.

For much of my career, the stability of the global economic system depended on decisions taken in Washington, DC—and on whether those decisions were bound by rules or by discretion. Working with American officials for decades, across multiple administrations and institutions, my years living in Washington were part of that experience. In moments of real pressure, I saw first-hand the seriousness with which many approached power—particularly the understanding that power must be constrained if it is to be legitimate and durable. That understanding mattered, and it shaped outcomes. I was...