A federal judge in Seattle on Feb. 3 temporarily blocked the enforcement of President Trump's travel ban. Here's what you need to know about the judge's ruling. (Natalie Jennings,Bastien Inzaurralde,Alice Li/The Washington Post)

A federal court recently enjoined Donald Trump’s executive order barring refugees and migrants from seven Muslim-majority nations. One of the main issues at stake in the growing legal battle over the order is whether the order qualifies as unconstitutional discrimination against Muslims. Despite a thin veneer of religious neutrality, the order does in fact target Muslims. And that should indeed lead courts to strike it down.

On its face, the order does not discriminate on the basis of religion. The text does not even mention Muslims or any other religious group by name. But the Supreme Court has long recognized that a seemingly neutral regulation qualifies as unconstitutional discrimination if the true purpose behind it is in fact to target a specific racial, ethnic, or religious group. It applied that principle to racial discrimination as far back as 1886, and more recent decisions apply it to discrimination on the basis of religion, as well. In a 1993 case, the Supreme Court struck down a seemingly neutral law banning cruelty to animals because evidence showed it to have been motivated by hostility to the Santeria religion.

I. Trump’s Order Targets Muslims.

In some cases, it is difficult to figure out the true motive behind a facially neutral law or regulation. But, as Brown University Professor Corey Brettschneider explains in an excellent article, that isn’t a problem here:

[A] closer look at the executive order’s origins makes clear that it is a direct assault on the fundamental constitutional values of equal protection and religious freedom. How do we know this? Because Trump’s adviser, former New York Mayor Rudy Giuliani, told us so.

Interviewed on Fox News on January 28, Giuliani explained how the administration’s immigration policy morphed from one that was obviously unconstitutional to one that is more subtly so. Host Jeanine Pirro asked, “Does the ban have anything to do with religion?” In response, Giuliani said, “When [Trump] first announced it, he said ‘Muslim ban.’ He called me up, he said, ‘Put a commission together, show me the right way to do it legally.’” “It,” in this case, of course, is a ban on Muslims. Giuliani’s admission is a textbook case of drafting an order in a way that avoids overt declaration of animus against a religious or ethnic group, while retaining the motive and much of the effect.

When you combine Giuliani’s admission with Trump’s own numerous statements advocating a Muslim ban, it’s hard to find a clearer case of discriminatory motives hiding behind a vener of neutrality. Even when Trump first shifted his proposal away from a facial ban on Muslims entering the US, he called it “an expansion” of his earlier explicit Muslim ban proposal rather than a repudiation of it. In other words, it was an attempt to target Muslims without saying so explicitly.

It’s hard to find a more blatant smoking gun in a case of this type than the one Trump and his minions have given us here. If this does not count as unconstitutional discrimination covered by a thin smokescreen of neutrality, it’s hard to see what does. Conservatives who may be inclined to support Trump’s order should remember that the same sorts of tactics could be used by blue states or a future Democratic president to target evangelicals or other theologically conservative groups (for example, in response to their refusal to provide services to same-sex weddings).

Some defenders of Trump’s order argue that it isn’t really targeted at Muslims because it only covers migrants from seven countries. Refugees from other Muslim nations are not affected. But a policy can be targeted at a group without sweeping in every member of it. For example, poll taxes and literacy tests in the Jim Crow South were clearly aimed at preventing blacks from voting even though some could get around it by passing the test or paying the tax.

Similarly, the unconstitutional motive behind Trump’s order can’t be sidestepped by pointing out that it blocks some non-Muslim refugees too. Poll taxes and literacy tests excluded a good many poor whites from the franchise, but were still clearly aimed at blacks. Just as the exclusion of some white voters was collateral damage from southern states’ efforts to target African-Americans, so the exclusion of Syrian Christian refugees is tragic collateral damage from Trump’s efforts to target Muslims.

Once the plaintiffs provide evidence that a facially neutral law or regulation may have an unconstitutional discriminatory purpose, the government has the burden of proving that it would still have adopted the policy in question even in the absence of any illicit motive. As the Judge James Robart put it in the oral argument held before he issued the order suspending enforcement of the order, the government must, at the very least, prove that its policy is “grounded in fact instead of fiction.” The administration is highly unlikely to be able to do that because the security rationale for the order is laughably weak. The policy actually undermines our security much more than it protects it. To quote Judge Robart again, “You’re here arguing on behalf of someone who says we have to protect the U.S. from these individuals coming from these countries, and there’s no support for that.”

II. The Plenary Power Doctrine.

If this were an ordinary discrimination case, Trump would have little chance of winning. But his order might still be saved by the so-called “plenary power doctrine,” which holds that the federal government has sweeping power over immigration issues, including overriding constitutional rights that constrain every other type of government policy. The Supreme Court has indeed at times ruled that the plenary power doctrine permits discrimination that would be forbidden in other contexts. But, as leading immigration law scholars Peter Spiro and Adam Cox explain, recent decisions suggest that the plenary power doctrine is not as robust as it once was, and might not stand in the way of invalidating Trump’s order.

The legal battle over the order is still in its early stages, and the ultimate outcome remains very much in doubt. But, so far, Cox and Spiro’s optimism has been vindicated by the string of preliminary victories those challenging the order have secured in several federal district courts.

I would add that the plenary power doctrine is ultimately indefensible and should be overruled by the Supreme Court. Nothing in the text or the original meaning of the Constitution indicates that immigration law is an exception to the constitutional rights that constrain every other type of government policy. The text does limit a few specific constitutional rights to American citizens, such as those protected by the Privileges or Immunities Clause of the Fourteenth Amendment. But this only underscores the fact that other constitutional rights extend to everyone. There would be no need to explicitly limit some rights to citizens if there were a general presumption that non-citizens are excluded.

Moreover, most of the rights enumerated in the Constitution are stated as generalized limitations on government power, not as privileges reserved to some specific group of people, such as American citizens or permanent residents. That is certainly true of the religious Free Exercise Clause of the First Amendment, the Equal Protection Clause of the Fourteenth Amendment, and the Due Process Clause of the Fifth Amendment, the three provisions at issue in the litigation over Trump’s order (the text of the Equal Protection Clause seems to limit its application to state governments, but the Court has long held that it restricts the federal government too). It is highly questionable whether the original meaning gives the federal government any general power to restrict immigration at all, much less one so sweeping that it overrides individual rights that restrict every other type of government action.

Some immigration restrictionists cite the Preamble of the Constitution as proof that the document does not protect aliens. I rebutted that claim here.

The origins of the plenary power doctrine lie not in the text of the Constitution but in the racial and ethnic prejudice of the same era that gave us Jim Crow and Plessy v. Ferguson. The Court should consign it to the same dustbin of history where Plessy has gone.

But striking down Trump’s order would not require the courts to overrule the plenary power doctrine completely. They need only rule that the doctrine is not so sweeping as to permit blatant religious discrimination unsupported by any reasonable security rationale.

UPDATE: This post originally included an incorrect link to the article where I rebutted claims that the Preamble of the Constitution denies all rights to aliens. I apologize for the error, which has now been fixed.