Since President Donald Trump invoked the Alien Enemies Act three months ago to send hundreds of Venezuelan immigrants detained in the United States to a notorious prison in El Salvador, much has been said about why the President’s actions are unlawful. For example, illegal migration and drug smuggling are crimes, not acts of war, and so do not amount to an “invasion or predatory incursion,” as the statute requires, and the government’s failure to give the people it was sending to El Salvador notice and an opportunity to be heard violated their constitutional right to due process.

There is one question, however, that has received little attention: whether the President’s use of the Alien Enemies Act was unlawful because it was not issued against a nation or government. The President can invoke the Alien Enemies Act only if there is a “declared war” against, or “invasion or predatory incursion” carried out by, a “foreign nation or government.” Trump claims that this requirement is met by Tren de Aragua, a criminal cartel with supposed ties to the Venezuelan government. But as my colleagues and I recently argued in an amicus brief, Tren de Aragua is not a “nation or government” under the Alien Enemies Act.

To better explain why, I lay out the current state of the Alien Enemies Act litigation; what the government and various courts have said about whether Tren de Aragua is a nation or government; and how the text and history of the Act establish that it is not a “nation or government” within the meaning of the AEA.

I. State of the Alien Enemies Act Litigation

In March of this year, President Donald Trump invoked the Alien Enemies Act to address what he called in a Proclamation the “Invasion of the United States by Tren de Aragua.” Later that day, the administration sent hundreds of Venezuelan immigrants detained in the United States to a maximum-security prison in El Salvador. It did so without giving any of them their constitutionally mandated day in court. Most of these men have not been heard from since.

Getting wind of this the day before the Proclamation was issued and their clients were loaded onto planes, the ACLU and Democracy Forward quickly went into court to try to stop the imminent removals. Chief Judge James Boasberg of the United States District Court for the District of Columbia ordered the government both not to remove these men and to appear at a hearing later that day. Despite this order, the government sent two planes loaded with Venezuelan immigrants to El Salvador in the middle of the hearing. A third plane took off after Judge Boasberg reiterated his order that the government could not remove anyone without even the semblance of a hearing.

After the D.C. Circuit denied the government’s emergency application to vacate Judge Boasberg’s temporary restraining order, the government asked the Supreme Court to weigh in. In a 5-4 ruling, the Supreme Court on April 7th, vacated Chief Judge Boasberg’s order on the narrow ground that any Venezuelan immigrant seeking to challenge their removal under the Alien Enemies Act had to do so through a habeas corpus petition in the district where they are detained. The Court declined, at that early stage, to decide whether the government could even invoke the AEA lawfully. But, as Justice Kavanaugh noted in a concurring opinion, “all nine members agree[d]” that the government cannot remove anyone under the Alien Enemies Act without “judicial review.”

Since then, Venezuelan immigrants detained around the United States have filed habeas petitions to stop the government from summarily removing them under the Alien Enemies Act. Most district courts moved quickly to block the government from removing anyone under the Alien Enemies Act in their district. But one court in the Northern District of Texas denied an emergency motion filed by two representatives, initials A.A.R.P. and W.M.M., on behalf of a class of Venezuelan immigrants detained in the Bluebonnet Detention facility outside of Abilene. Many of the Venezuelan men held at the Bluebonnet detention facility had been transferred from detention centers around the country to one of the few districts where there was not an active judicial order prohibiting the government from immediately deporting people under the Alien Enemies Act. Judge James Hendrix denied the application principally on the ground that the government promised not to deport the two named plaintiffs. The night after that decision, the ACLU once again got wind that the government planned to remove several Venezuelan immigrants in that district under the Alien Enemies Act with no more than a night’s notice in direct contravention of the Supreme Court’s April 7th order. It immediately asked the district court to stop the unconstitutional removals. When the district court did not immediately respond, the Supreme Court once again stepped in and, in an extraordinary 1 a.m. order on Saturday, April 19th, temporarily blocked the government from “remov[ing] any member of the putative class of detainees from the United States until further order of this Court.”

The case, now styled W.M.M, et al. v. Trump, et al., was remanded to the Fifth Circuit to proceed “expeditiously.” Oral argument is set for Monday, June 30th.

II. What the Government and Other Courts Have Said About Whether Tren de Aragua Is a Nation or Government

In his Proclamation, Trump claimed that Tren de Aragua “is closely aligned with, and indeed has infiltrated, the Maduro regime.” The Proclamation states that Nicolas Maduro, “who claims to act as Venezuela’s President” “coordinates with and relies on” Tren de Aragua and other criminal organizations “to carry out its objective of using illegal narcotics as a weapon to ‘flood’ the United States.” It concludes by stating that Tren de Aragua “is undertaking hostile actions and conducting irregular warfare against the territory of the United States both directly and at the direction, clandestine or otherwise, of the Maduro regime in Venezuela.” Based on those justifications, the Proclamation declared that “all Venezuelan citizens 14 years of age or older who are members of [Tren de Aragua], are within the United States, and are not actually naturalized or lawful permanent residents of the United States are liable to be apprehended, restrained, secured, and removed as Alien Enemies.”

Most courts have not yet ruled on this question. But those that have ruled have essentially sidestepped the issue. And the issue hasn’t yet been critical to any court’s decision about the legality of the President’s invocation of the AEA. In one case called J.A.V., et al. v. Trump, et al., for example, Judge Fernando Rodriguez, Jr., of the United States District Court for the Southern District of Texas held that the government could not invoke the Alien Enemies Act against Tren de Aragua because it had not perpetrated an “invasion or predatory incursion.” But, in dicta, Judge Rodriguez also took the position that, because the government claims that Tren de Aragua is carrying out its crimes at the behest of the Venezuelan government, and everyone agrees Venezuela is a “foreign nation or government,” this prong of the Alien Enemies Act could be satisfied.

Up until now, the government has spent little of its briefing space in the litigation defending the Proclamation’s assertion that Tren de Aragua is a “nation or government.” But what it has argued is telling. The government, importantly, has conceded that Tren de Aragua is not a “nation.” Instead, it is now arguing that Tren de Aragua is a “government” within the meaning of the Alien Enemies Act because “Venezuela operates as a hybrid-criminal state with [Tren de Aragua] and other criminal organizations.” In other words, the government currently contends that, because Tren de Aragua is a “proxy” for Venezuela, an attack by that criminal cartel is an attack by Venezuela.

Putting aside the fact that most of the government’s own intelligence agencies have concluded that Venezuela’s President does not control Tren de Aragua, our amicus brief demonstrates why, under both the text and history of the Alien Enemies Act, Tren de Aragua is not a nation or government within the meaning of the Act.

III. Tren de Aragua Is Not a “Nation or Government” Under the Alien Enemies Act

The lawmakers who passed the Alien Enemies Act in 1798 understood the terms “nation” and “government” to be defined by the law of nations, a set of international norms that governed foreign relations between nations at the time. The law of nations set two interrelated qualifications for any entity to be considered a nation or government: self-definition and foreign recognition. To be a nation or government, an entity had to hold itself out as acting on behalf of a group of people living in a defined territory. It also had to be recognized by other nations as speaking on its people’s behalf on the international stage. These were the very qualities that the Founders thought were necessary for the American Revolution to turn thirteen colonies into a new nation.

The AEA’s history underscores why the Act can only be invoked against nations or governments that meet these qualifications. The AEA was passed in response to an ongoing conflict with one “foreign nation or government” in particular—the French Republic. In 1798, the United States was in the midst of what was known as the Quasi War with this erstwhile ally. In response, Congress passed the Alien Enemies Act and its counterpart, the notorious Alien Friends Act. The Alien Friends Act granted the President sweeping power to detain and expel any noncitizen deemed “dangerous to the peace and safety of the United States.” It was immediately attacked as unconstitutional and shortly thereafter allowed to lapse in disgrace.

The Alien Enemies Act, by contrast, was widely considered constitutional. The reason for this disparity was simple: the Alien Enemies Act was understood to be an extension of Congress’s power to declare war. During a state of war, as James Madison explained at the time, Congress had the power “under the law of nations” to hold foreign citizens accountable for the belligerent actions of their home country. But only a nation or government under the law of nations—an entity that claimed the authority to act on its people’s behalf and was recognized as having that authority—could demand the sort of allegiance from its people that would justify holding them personally accountable for their sovereign’s actions during war.

This is a high bar. That is why the Alien Enemies Act has previously been invoked just three times: during the War of 1812, World War I, and World War II. And each time, the United States was in a state of war against an entity that both held itself out and was formally recognized as a sovereign nation or government acting on behalf of the people in its territory.

Tren de Aragua meets neither of these criteria. It has never claimed to govern on behalf of any inhabitants of a defined territory, and neither the United States nor any other nation has recognized it as having the authority to act on Venezuelans’ behalf. Quite the opposite—on his first day in office, President Trump designated the criminal cartel a “Foreign Terrorist Organization” that threatens the security of both Venezuela and the United States.

Neither the government, in its defense of the President’s Proclamation, nor the courts, in addressing the issue, have really grappled with all the obvious ways in which Tren de Aragua is not a “nation or government.” Instead, the government is now trying to sidestep the issue entirely by conflating Tren de Aragua and Venezuela. But Trump did not invoke the Alien Enemies Act against Venezuela. He chose to target Tren de Aragua specifically. Whatever the national security interests behind that choice, the government must now own its consequences. A Proclamation, under the Alien Enemies Act, is not simply a piece of paper; it is, much like a declaration of war, a “valuable constitutional ritual” that “increases the political and moral accountability of [our] political actors.”

Throughout the Alien Enemies Act litigation, the government has argued that courts do not have the authority to second-guess the President’s declaration. But it is emphatically the role of courts to interpret the text of statutes like the Alien Enemies Act and decide whether Tren de Aragua qualifies as a “nation or government” within meaning of that text. It clearly does not.