Once a decade, the leaders of the world's two largest powers meet face to face, and in that meeting the whole architecture of global order is briefly made visible. Donald Trump welcomed Xi Jinping to Washington with rare ceremonial honors — a red carpet, a flyover, the full theater of state — not because the hard questions have grown easier, but because both sides understand that the appearance of stability is itself a form of governance. With trade, artificial intelligence, Taiwan, and regional conflicts all unresolved, this three-day summit is less a negotiation than a signal: that despite d