With these moves, the United States may be hoping to protect the interests of American tech companies, but that doesn’t mean it’s wrong about the threat of Chinese spying. That’s real, and laid out in the open: Just look at China’s 2017 National Intelligence Law.

The N.I.L. is no standard security and spying legislation, concerned principally with preventing the leak of state secrets. Its main thrust isn’t protective; it’s proactive. “All organizations and citizens shall support, assist and cooperate with national intelligence efforts according to the Law,” it says. (I know of no official English version; this is my translation, based partly on several others.) Another provision is even more explicit: The state institutions tasked with enforcing the N.I.L. — which also oversee all intelligence and espionage activities, civilian and military — “may demand that relevant organs, organizations and citizens provide necessary support, assistance and cooperation.” Spying for the state is a duty of the citizens and corporations of China under the law, much like paying taxes.

The N.I.L. offers enticements for compliance: “The state gives commendations and rewards to individuals and organizations that make major contributions to national intelligence efforts.” In its January indictment against Huawei, the United States claims that the company systematically gives bonuses to employees who pilfer intellectual property from foreign companies.

The N.I.L. leaves little room for opting out. “Obstructing the work” of China’s intelligence institutions is punishable and may be a criminal offense. Those institutions are entitled to “have priority use of, or can lawfully requisition the transportation or communications tools, premises and buildings of state organs, organizations or individuals” — and “when necessary,” set up “relevant work sites and equipment within them.” In other words, installing a back door in Huawei hardware to collect foreign intelligence would have a firm basis under Chinese law.

During an interview with CBS last month, Ren Zhengfei, the founder and chief executive officer of Huawei, was asked if he had “ever given any information to the Chinese government, in any way, shape or form?” Mr. Ren — who is also Ms. Meng’s father, as well as a veteran C.C.P. member and a former officer of the People’s Liberation Army — answered: “For the past 30 years, we have never done that, and the next 30 years to come, we will never do that.”