By Zachary Karabell

The U.S.-China relationship seemed to improve last week at the G-20 summit in Argentina, where President Trump announced he had reached an important agreement with President Xi Jinping. Then, an ominous development: American authorities asked Canada to arrest the chief financial officer of one of China’s largest technologies companies for alleged sanctions fraud and violations of U.S. export controls. Meng Wanzhou isn’t just a top leader at Huawei, which makes phones and other gadgets; she is also the daughter of the company’s founder and chairman, which makes her arrest somewhat like the Chinese arresting the daughter of Steve Jobs if she had helped run Apple. It would be an understatement to say that Beijing did not react well: It demanded her release and accused the U.S. government of violating the rights of a Chinese citizen.

The timing could hardly be worse, and from what can be told, it reflects the overall chaos of the Trump administration. National security adviser John Bolton claimed he was informed of the pending arrest by the Justice Department but did not pass that information to the president. That no one in the White House considered the implications of her arrest on the tenuous trade truce between China and the United States is itself rather astonishing.

The case against Huawei and its executives may be legitimate under U.S. law, but it is nonetheless a hideous political mistake. Perhaps Huawei used American-made components in equipment it sold to Iran, violating U.S. sanctions. But even in less ambiguous cases, there is always such a thing as prosecutorial discretion. Not every case that can be brought should be brought, and not every case should be prosecuted to the full letter of the law. In international cases, that is doubly true. If the United States wants to respond to China’s rise and manage the changing role of the United States in the international system, it could hardly have picked a dumber tactic.

Even if everything alleged is correct, however, the quest against Huawei is a ridiculous overreach — predicated on an assumption that the United States can dictate how foreign competitors conduct business. Yes, the company has deep ties with the Chinese Communist Party, though it’s worth mulling whether those are any more pernicious than the close bonds that connect defense contractors such as Boeing and Lockheed with the Pentagon.

More important, global supply chains are now deeply interconnected and touch multiple countries and numerous companies. Samsung, for instance, is the second largest cellphone provider in Iran, behind Huawei, while the Swedish telecom company Ericsson has been selling equipment to Iran even under the sanctions. Those companies may have done a better job not using American components for products sold to those countries, though with the complexity of global component sourcing, it is unlikely that no American intellectual property has been used by Iranian consumers. Yet U.S. prosecutors are not trying to curtail the work of those mega-technology giants, or aggressively investigating where every component originated.