Think of it as Xi Jinping’s Himalayan blunder. The final outcome of the border standoff between China and India may be uncertain, but the consequences of New Delhi’s decision last week to ban 59 Chinese apps, including the popular video-sharing app TikTok, are clear. Should the ban stick, and be emulated by other countries, it could seriously set back Beijing’s ambition to replace the U.S. as the world’s dominant technological power.

“Chinese companies can’t really be global if they lose out on India,” says Rush Doshi, an…