He says that they are a security threat. If so, it is time to show the world the evidence. President Trump’s plan to severely restrict the popular WeChat and TikTok apps could be viewed as a tit-for-tat for China’s yearslong prohibition of American services like Facebook and Google. But I’d like to think we’re better than that. The president has cited security concerns in his quest to force the sale of the U.S. operations of TikTok to an American firm, setting off a bidding war that reached its nadir when he called for a fee to be paid to the...