The US's Huawei trade blacklist has been in place for almost half a year. Now Microsoft's top lawyer and president Brad Smith says the US government should provide evidence for cutting off the Chinese company from US technology.
Smith said the current restrictions on Huawei, the world's second-largest smartphone maker, are wrong.
In May the US Department of Commerce put Huawei on the Entity List, effectively banning all Western firms from supplying it technology.
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Smith told Bloomberg Businessweek that the ban shouldn't be imposed without a "sound basis in fact, logic, and the rule of law".
The official line from the Whitehouse is that Huawei is a genuine national security threat to the US. However, Smith said the US government has shown Microsoft – which supplies Windows 10 for Huawei PCs – no evidence to back up the current stance.
"Oftentimes, what we get in response is, 'Well, if you knew what we knew, you would agree with us'," he said. "And our answer is, 'Great, show us what you know so we can decide for ourselves. That's the way this country works'."
Last month the Department of Commerce gave US firms a 90-day extension for exceptions to the trade ban that's been in place since May. Google recently clarified that its license for exceptions to the ban is valid for existing Huawei products but not new Huawei products.
The restrictions aren't technically related to ongoing US-China trade negotiations. However, president Trump has said Huawei's situation could be resolved if China agreed to an acceptable trade deal with the US.
Trump in late August said Apple CEO Tim Cook made a good case that US tariffs harm it and help smartphone rival Samsung, shortly after deferring the introduction of a new round of duties on $300bn of Chinese imports, which include phones and laptops.
Microsoft could also be harmed by potential Commerce Department export restrictions on artificial intelligence and quantum computing. Smith told Bloomberg that "you can't be a global technology leader if you can't bring your technology to the globe".
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The lawyer says Microsoft has argued that the department should take a "scalpel" as opposed to a "meat cleaver" approach and asked it to limit bans to sales that might pose a national security risk, such as to universities with ties to the Chinese military.
Smith also posed an analogy for the situation Google, Microsoft, Apple, Arm, and Qualcomm face in terms that Trump might understand: hotels and beds.
"To tell a tech company that it can sell products, but not buy an operating system or chips, is like telling a hotel company that it can open its doors, but not put beds in its hotel rooms or food in its restaurant. Either way, you put the survival of that company at risk."