On Tuesday, Huawei filed a legal motion challenging a government ban on its equipment as unconstitutional. It’s the latest effort by the Chinese tech company to push back against policies limiting its global reach.

Huawei is currently struggling with an existential threat to its business after the US Commerce Department blocked the company from contracting with US companies without government approval. The ban, instituted earlier this month, has already forced companies like Google to suspend work with the Chinese tech giant.

That order is just the latest effort by the US government to push Huawei out of the country. Before the wider ban, Congress passed a law barring Huawei products from use in the government, labeling them a potential security threat. That ban not only blocked government agencies from using the products, but any contractors hoping to score lucrative government contracts also had to drop Huawei equipment. Facing the ban, Huawei filed a lawsuit against the US in March, saying the action was unconstitutional.

That suit is still ongoing, and we now have more insight into Huawei’s legal argument through a motion filed last night, which sketches out why the company believes the government ban should be nullified. The motion asks a court to rule directly as a “summary judgment.”

As legal experts anticipated, Huawei is arguing that the government ban is “a bill of attainder.” Under the constitution, Congress is forbidden from passing laws that target specific people, and Huawei says the ban qualifies.

In the document filed by Huawei — which starts with a quote from James Madison — Huawei says Congress overstepped the law when it passed legislation that imposed the ban. Huawei was singled out by name in the defense budget, which included the ban, and the company says the measure “denies Huawei any procedure for providing rebuttal” to the decision. In soaring language, Huawei’s attorneys argue the legislation “produces the very tyranny which the Framers feared” and should therefore be ruled unconstitutional.

The US government has repeatedly argued that Huawei equipment could be used by the Chinese government to spy on American networks and that banning companies like Huawei is well within its national security powers. (Huawei has denied that its tech could be used to spy on the US.)

The company points to precedent reaching back to the Civil War and Cold War when the courts struck down actions against former Confederate soldiers and members of the Communist Party. The Huawei ban, the company says, is similarly “selective” and “punitive”: it “imposes the kind of permanent disability on serving the Government and/or pursuing the avocation of one’s choice that has historically been viewed as punishment.”

Huawei, the company says, has been branded “disloyal” through an act of legislation, rather than having an opportunity to make its case in the courts. This has also deprived it of due process under the law, it argues.

The company’s case faces a number of challenges. After concerns over cybersecurity, the US instituted a federal ban on software from Russia-based Kaspersky Lab, a clear precedent to the Huawei order. Kaspersky also filed a legal challenge, arguing that the government had created a bill of attainder, but the government prevailed in court. In general, the courts have given wide latitude to the government on national security issues, rendering Huawei's legal prospects uncertain.

The wider ban, which affects sales of American products to Huawei, raises its own set of legal issues. Whether Huawei will also take legal on that front remains to be seen, but this week's legal maneuvering gives some indication of what the arguments in that case could look like. (As trade negotiations with China continue, Trump has suggested the Huawei ban could be lifted as part of a deal, raising questions about the administration’s national security rationale.)

In a statement accompanying the motion, Huawei's chief legal officer said the continuing crackdown “sets a dangerous precedent.”

“Today it’s telecoms and Huawei,” he said. “Tomorrow it could be your industry, your company, your consumers.”