Ten days into President Trump's Iran campaign, the war has gone global.At least 20 countries are now militarily involved — shooting, shielding or quietly supplying — while a widening energy shock punishes nations far from the front lines.Why it matters: This isn't World War III. But it may be the closest we've come in decades — drawing in more countries, more great powers and more overlapping conflicts than any crisis since the Cold War.Zoom in: Iran has struck at least 10 countries since the wa...