China Speared Then Perhaps Retaliates Presumptive Democratic presidential nominee Joe Biden’s accusation that his rival, President Trump, has been too soft on China has launched a campaign battle focused like a laser on Beijing. The rhetoric is heated, and China has to skillfully play a role in a democratic debate for which authoritarian regimes are generally unskilled. Mr. Trump argues that Beijing wants Biden to win, and no doubt it does. Mr. Biden is at least predictable. But for American farmers, they want China to make its committed Phase One agricultural purchases. If it looks like Biden has a clear edge, it would be tempting for Beijing to stop making the purchases in order to hand the Trump Administration a failure. However,...