This morning, ARM announced that it was cutting ties with Huawei, in the interest of “complying with all of the latest regulations set forth by the U.S. government.” It’s a catastrophe for Huawei’s device business, halting its access to current and future chip designs and coming on the heels of similar breaks from Google and Microsoft. Huawei is in deep, deep trouble, and we still don’t have a clear picture of why.

Security experts have been warning about Huawei for more than a year, but it’s only in the last week that those warnings have escalated into an all-out trade blockade on the company’s US partners. There’s never been a full accounting of why the US government believes Huawei is such a threat, in large part because of national security interests, which means much of the evidence remains secret. But it’s worth tracing out exactly where the concerns are coming from and where they could go from here.

There are real and serious concerns about Huawei providing cellular network gear

The first wave of concerns about Huawei had more to do with cell towers than cellphones. Huawei is one of the main suppliers for network infrastructure (basically, the hardware that your phone connects to), alongside Ericsson and Qualcomm. As carriers raced to build out 5G networks, lawmakers rushed to keep Huawei hardware out of whatever was being built.

Huawei’s device business has become collateral damage in a broader fight over 5G

There was never any hard evidence of backdoors in Huawei’s cell towers — but, as hawks saw it, there didn’t need to be. As a hardware provider, Huawei needs to be able to deploy software the same way Apple deploys iOS updates. But as long as there was a pipeline from Huawei’s China headquarters to cell towers in the US, there would be a strong risk of Chinese surveillance agencies using it to sneak malware into the network, whether they did it with Huawei’s help or by hacking themselves into the middle. As intelligence agencies saw it, the risk was just too great.

That might not seem fair, but it’s at least a logical response to a real concern. Cell networks are a very tempting target for espionage, and China has a long history of this kind of spying.

The ban on licensing Android and other components seems more like a trade issue, not a security issue

But what’s happened over the past week goes a lot further and doesn’t make quite as much sense. The order handed down on Friday bans US companies from doing business with Huawei, which resulted in Google and a string of other companies cutting ties. But that rule has to do with what US companies sell, not what they buy. Because Huawei doesn’t sell phones in the US, the most popular Huawei products affected would never be shipped here.

As a result, it’s hard to see the latest action as protecting any national security interests. Revoking Huawei’s Android license doesn’t matter for US network equipment, nor does Huawei’s access to ARM chip designs. Instead, it feels like Huawei’s device business has become collateral damage in a broader fight over 5G.

By hastily invoking emergency powers, the White House has largely avoided making a public case for why the blacklisting was necessary — a move that’s already causing political damage. Still, the simplest explanation is that Huawei has behaved too badly to be trusted after years of quiet intellectual property violations and trade secrets theft.

But if that’s the problem, it could set a troubling standard for other Chinese companies in the future, particularly given the broad scope of the executive order. It made sense to target the infrastructure ban at Huawei since it was the only Chinese company that could plausibly build network infrastructure for the US. But if the concern is predatory behavior by Chinese companies, there are lots of other outfits that could be exposed. The same Corning glass that’s shipped to Huawei is being shipped to Xiaomi; the same Intel processor in Huawei’s MateBook is in lots of Lenovo laptops, too. The question is how far the White House wants to push its case and how China will respond.

For more, watch the video above.