Sweeping narratives can soon take hold, even if critics are already pointing to their holes. In the 1990s, two such theses quickly took root. The first was that liberal democracy had triumphed. The second was that technology would inevitably bring liberation; Bill Clinton quipped, in reference to China, that trying to control the internet would be like nailing jello to the wall. Beijing proved both wrong, helping to spell an end to the end of history, and demonstrating – ever more enthusiastically – that technology’s transformative powers can not only be curbed, but harnessed to the forces of repression.

In these gloomier times, the threat that technology will lead not to freedom but to surveillance, control or disruption from authoritarian adversaries has greater resonance – and more supporting evidence. The Trump administration has been pressing its allies to ban the Chinese telecoms equipment giant Huawei from participating in their 5G networks, arguing that it could be used by the Chinese state for spying or even attacks upon democratic nations. Huawei insists it has been traduced, is independent of the Chinese state and would never compromise a client.

The difficulty in such situations is not challenging the wilder rhetoric on each side, but trying to understand and address the precise challenges beneath the dispute. This should be what Theresa May has sought to do in giving the nod to Huawei’s involvement in Britain’s 5G network, while limiting its equipment to “non-core” parts. (Some suspect a tactical attempt to navigate a path between the wrath of Washington and Beijing.)

For both the US and China, intellectual and economic interests and abilities are increasingly linked to political and military ones as technology develops. It is increasingly hard to draw the kind of clear lines that help to define and answer policy challenges. As China rises, the US is increasingly anxious about its own place in the world. The US has repeatedly complained about Chinese industrial espionage, including through hacking, and recently indicted Huawei for stealing trade secrets as well as sanctions-related fraud; the company denies the charges. The fury with which Beijing responded gives all the evidence needed of the importance it accords Huawei.

But it is not only the US and its western allies who are concerned about Beijing’s reach. The entrenchment of party control over business and society at home, and its growing forcefulness overseas, as well as its record of commercial and other hacking, have made many countries nervous.

Turning from arguments to facts is not as helpful as it should be. One problem is that key issues are disputed. After Australia banned Huawei from its new network, despite its heavy reliance on trade with China, its spy chief warned that the distinction between core and non-core collapses with 5G: “A potential threat anywhere in the network will be a threat to the whole network.” Yet now the US has rowed back from its direst threats of non-cooperation with countries using Huawei gear, stating only that none of the Five Eyes intelligence sharing nations will use it in the “sensitive” parts of their networks.

A second problem is that this is by necessity a hypothetical argument, and when it is not, it will be too late either way. As Huawei points out, no one has produced any evidence that it has ever compromised a client. But as its critics note, it is easier to hide than to find back doors; and if the Chinese party state demanded it do so in future, the lack of a free media, civil liberties groups, political opposition or independent judiciary mean that we would never know.

That the UK is making its own decisions on security is right and proper. But Britain has been much too casual about its use of Huawei equipment in the past. Compromised equipment is not the only risk: whoever provides the gear, the danger of exploitation of vulnerabilities in the system, or human frailties, remains high. Huawei’s inclusion rams home the case for the highest level of vigilance at every stage. Mrs May has decided to trust. Britain must keep verifying.