The US-Japan alliance has never been more important or stronger. And rarely has it faced greater uncertainties or dangers. That’s the paradoxical takeaway from my trip last week to Tokyo, where I spoke to government and private-sector audiences about the state of the world. Japan faces growing threats in its neighborhood, from a bellicose China and a potentially provocative North Korea. But the state of America was the foremost worry of nearly everyone I met. Washington’s alliance with Japan has been an inspiring reminder that friendship can follow bitter enmity. It has anchored the US security presence in the Pacific for decades and looms ever-larger today. The risk of conflict in that region is rising, and America’s military edge is slipping. That means Washington will need greater support from its friends — and it makes Japan, America’s most powerful ally in the world’s most crucial region, utterly indispensable. On many dimensions, the relationship is thriving. Japan is muscling up militarily, by planning to nearly double defense spending between 2022 and 2027. Tokyo and Washington are gradually turning what was once a deeply asymmetrical alliance — a strategic protectorate, really — into a genuine warfighting partnership.

Full opinion : Trump’s tariffs are the first crack in the most important security partnership in the Pacific.