*This is the fifth post in a series on Adam Cox and Cristina Rodríguez’s book, The President and Immigration Law. For earlier posts in the series, click here.

Adam Cox and Cristina Rodríguez have written what is likely to become the definitive work on presidential power over immigration. As they describe, the executive branch has come to wield vast discretionary authority over immigration policy, even though nothing in the text or original meaning of the Constitution grants it such authority. At the time of the Founding, the dominant view was that the Constitution did not give the federal government any general power to exclude and deport immigrants at all, much less that such authority would come to rest in the hands of a single person and his subordinates.

Their diagnosis of the problem is sound, and so are many of their proposals for reform. But they understate the importance of eliminating constitutional double standards in immigration law. In addition, the issues they highlight cannot be properly addressed unless we make it easier for potential immigrants to enter the US in the first place, not just constrain deportation after the fact.

As Cox and Rodríguez explain, the executive has gradually acquired “extraordinary power over immigration policy” due to a combination of extensive delegation by Congress, and the enormous size of the undocumented immigration population subject to deportation (some 11 million people). Since there is no way to deport all of the latter or even come close, presidents end up wielding vast discretion over who to target and why. Cox and Rodríguez’s book insightfully analyzes the growth of this discretionary authority, and the ways in which presidents of both parties have used it – sometimes to give a reprieve to favored groups, and other times to engage in brutal enforcement actions that consign large numbers of people to lives of poverty and oppression.

Such laws as Section 212(f) of the 1952 Immigration and Nationality Act – the provision used to justify Donald Trump’s anti-Muslim travel ban, upheld in Trump v. Hawaii (2018), have also been interpreted as giving the president nearly unlimited power to block migrants from entering the United States to begin with – even if they could otherwise legally do so. As a result, the president has acquired the power to exclude almost any migrant from entering the United States, while simultaneously being able to pick and choose which of many millions of eligible people to deport. In many cases, this literally amounts to the power of life and death, as when the president deports people to places and situations where their lives are at risk or blocks the entry of refugees fleeing persecution and war. Cox and Rodríguez refer to the situation as a “two-principals model,” in which the President has power over immigration law comparable or even somewhat greater than that of Congress. They are right, but that characterization may even, to a degree, understate the enormous power of the executive.

Some of this discretionary power is just one part of a broader problem with our legal system. There are far more laws than any administration can possibly enforce, and far more lawbreakers than can ever be caught and prosecuted. As a result, a large majority of adult Americans have violated federal criminal law (to say nothing of state law) at some point in their lives, and could potentially be prosecuted . Undocumented immigrants are far from the only people who remain free only because of resource constraints and the exercise of executive enforcement discretion. But the immigration situation is particularly severe, because of the grave consequences of deportation, and the weakness of due process protections in the immigration enforcement system.

Cox and Rodríguez propose reforms that could help address the problem of excessive executive discretion to deport and exclude migrants. Most notably, they argue that Congress “must drastically decrease the number of people who live under the threat of enforcement” by legalizing the presence of at least a large part of the undocumented population (currently estimated at 11 million people). They also suggest giving the president greater discretion to admit and legalize new immigrants. The Biden Administration’s proposed American Citizenship Act would, if enacted (which remains doubtful) go a long way to achieving the former goal. Some key elements recently passed the House of Representatives.

But Cox and Rodríguez underestimate the importance of eliminating constitutional double standards under which immigration policy has largely been exempted from constitutional constraints that apply to nearly all other government policies. The most obvious recent manifestation is the Supreme Court’s decision in Trump v. Hawaii, which upheld Trump’s travel ban against residents of several Muslim-majority nations, despite extensive evidence of discriminatory motivation that would have been enough to invalidate a similar policy in almost any other area.

Cox and Rodríguez contend that Trump v. Hawaii is an aberration and a “dramatic departure from the past.” In some respects, that is true, particularly in so far as it defends the immigration double standard much more blatantly than any other recent decision. But, unfortunately, the ruling is part of a much broader pattern in which both courts and executive branch officials refuse to apply rigorous constitutional constraints to immigration policy.

Among other things, immigration detention and deportation are not subject to anything like the same due process constraints as other severe deprivations of liberty. This results in such horrors as toddlers “representing” themselves in deportation proceedings, because there is no right to the provision of counsel to indigent migrants facing deportation. Procedural safeguards in immigration proceedings are so weak that the federal government routinely detains and deports thousands of US citizens, because authorities do not figure out their mistake until it is too late. Similarly, even the liberal Obama administration concluded that large-scale racial profiling should be permitted in immigration enforcement, though progressives would never accept such a thing in almost any other type of law enforcement. Weak constitutional standards play a major role in the deportation and detention state that Cox and Rodríguez refer to as the “shadow system” of immigration law.

Ending such double standards would bring immigration policy more in line with the text and original meaning of the Constitution. It also would curtail some of the worst aspects of the immigration system – including some of the worst abuses of the shadow system. The president could not so easily detain and deport large numbers of people if such actions were subject to normal constitutional constraints, as opposed to severely watered-down ones. If the Supreme Court refuses to reconsider Trump v. Hawaii and related cases, Congress can address the issue by passing such legislation as the No Ban Act (included in Biden’s broader immigration reform bill), and mandating strong procedural protections in immigration enforcement.

But even if constitutional double standards were eliminated and much of the undocumented population legalized, the president would continue to have vast enforcement discretion so long as the law makes it virtually impossible for most would-be immigrants to enter the United States legally. The president would still have enormous discretion to pick and choose whom to exclude at the border. Indeed, weakening deportation authority might actually incentivize presidents – especially those seeking to appeal to nativist political constituencies – to engage in greater efforts at preemptive exclusion.

Part of this problem can be alleviated by repealing Section 212(f), which the Supreme Court has interpreted as giving the president the power to exclude virtually any potential migrant whom he deems “detrimental” to American “interests” (without having to actually provide evidence of the supposed “detriment”). Elsewhere, I have argued that such broad presidential discretion is inconsistent with constitutional nondelegation principles. A recent federal district court decision striking down Trump administration restrictions on work visas agrees.

But, ultimately, broad presidential discretion to exclude migrants can only be alleviated by making it easier for them to enter legally in the first place. As discussed much more fully in my recent book Free to Move: Foot Voting, Migration and Political Freedom, the ultimate goal should be a system where the current presumption of exclusion unless specifically authorized by law, is replaced by a presumption of freedom of movement, similar to that which exists for internal migration between state and local governments. That would largely put an end to a system under which we forcibly consign millions of people to lives of poverty and oppression simply because they were born to the wrong parents in the wrong place – a state of affairs that has strong parallels to medieval feudalism and Jim Crow-era racial segregation. If we restricted interstate movement in the same way as immigration, there would be massive enforcement discretion and associated abuses of power with respect to the latter, as well (as indeed occurred when state governments had greater power to exclude internal migrants in the nineteenth century). In the book, I outline numerous “keyhole solutions” by which potential negative side effects of free migration can be addressed by means less draconian than exclusion – and more beneficial to immigrants and natives alike.

The presumption of freedom of movement is unlikely to be fully achieved anytime soon, if ever. But there are many ways to make incremental progress by liberalizing immigration policy at the margin. Those who seek to reduce deportation, civil liberties violations, and excessive executive discretion associated with immigration policies would do well to focus on making it easier for immigrants to legally enter the United States in the first place.

Ilya Somin is a law professor at George Mason University and author of Free to Move: Foot Voting, Migration and Political Freedom.