Narendra Modi’s reappearance in China after a seven-year absence wasn’t penciled in for symbolism alone. The SCO summit in Tianjin gave him a stage at a moment when India’s exporters are taking real hits from U.S. tariffs, and domestic pressure to ease the strain is building. For Modi, shaking hands with Xi Jinping and Vladimir Putin wasn’t about pageantry—it was about demonstrating that India...