This inference from the text is backed by founding-era practice. During that period, it was assumed that even suspected pirates captured at sea, whether U.S. citizens or not, were protected by the Bill of Rights and therefore entitled to the due process of law guaranteed by the Fifth Amendment. Immigrants surely deserve at least as much protection as alleged pirates.
During the founding era, the dominant view, held by Founding Fathers including Thomas Jefferson and James Madison (the “father of the Constitution”), was that the federal government did not even have a general power to restrict immigration. The Supreme Court did not decide that Congress had a general power over immigration until the Chinese Exclusion Case of 1889, a ruling heavily influenced by racial prejudice. It is perverse that the exercise of a federal power that rests on such dubious foundations is largely exempt from the judicial scrutiny that applies to almost all other powers.
Admittedly, since the late 19th century, many Supreme Court precedents have reinforced the so-called plenary power doctrine, which holds that normal constitutional constraints on federal authority largely do not apply to immigration restrictions. For example, a variety of Supreme Court decisions hold that migrants could be excluded based on their political views, and based on restrictive laws whose enactment was in large part motivated by racial and ethnic prejudice. But these precedents are not as clear as is often assumed. Many upheld discriminatory immigration restrictions when similar discrimination was also permitted in the domestic context. For example, some involved racially discriminatory restrictions at a time when courts also upheld domestic Jim Crow laws, and others upheld the exclusion of communists at a time when courts permitted domestic persecution of communists as well.
Still, in addition to rejecting the reasoning of the travel-ban decision, uprooting the plenary power theory entirely would require reconsideration of the traditional interpretations of many earlier precedents, even though it would not require fully overruling those cases. The Court could instead accept that those precedents were justifiable insofar as they upheld discrimination that was also considered permissible in other areas of law at the time, but reject the idea that they require perpetuation of a double standard between immigration law and other fields.
Rejecting that view is the right course. The plenary-power doctrine has no basis in the Constitution. It was born of the racial and ethnic bigotry of the late 19th century, and deserves to suffer the same fate as Plessy v. Ferguson and other products of that mind-set.
Abolishing constitutional double standards in immigration law would not end all immigration restrictions. But it would ensure that immigration policy is subject to the same constitutional constraints as other exercises of federal authority. The government could still restrict immigration based on a variety of characteristics. For example, it could still discriminate using such criteria as migrants’ education, occupational credentials, and criminal records. But it would no longer be permitted to engage in racial, ethnic, religious, or other discrimination that is forbidden in other contexts.
Ending this double standard will not be easy, and probably cannot be done by lawyers alone. The civil-rights movement, the feminist movement, and the gun-rights movement are all examples of how successful struggles to strengthen protection for constitutional rights usually require a strategy that integrates litigation with political mobilization. The lessons of that history might be useful to those who seek to end one of the most egregious double standards in our constitutional jurisprudence.