The Volokh Conspiracy

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Keeping Out Hitler: Can Immigration Restrictions be Justified by the Need to Exclude Individuals who Might Cause Extraordinary Harm?

Critics of immigration restrictions often cite immigrants who make extraordinary contributions to the society. But what about the opposite case of immigrants who cause massive harm (like Hitler)? The argument deserves to be taken seriously. But it's ultimately much weaker than it seems.


Adolf Hitler.


Opponents of immigration restrictions – myself included—often cite the examples of immigrants who make extraordinary contributions to society. For example, immigrants contribute disproportionately to major entrepreneurial and scientific innovations, such as the development of the first two successful Covid vaccines approved by the FDA.  The immigrants in question probably would not have been able to make these contributions if they were confined to their countries of origin. Even if only a tiny fraction of immigrants achieve such feats, migration restrictions cumulatively forestall a substantial number of such accomplishments, thereby causing great harm that goes beyond the losses incurred by keeping out immigrants who "only" make ordinary economic and social contributions.

But what of the opposite scenario: individual immigrants who cause extraordinary harm. By "extraordinary harm," I don't mean immigrants who do things like commit ordinary crime or become a burden on the welfare system. I mean people who have a large negative impact on society as a whole, comparable in scale to the positive impact of a major entrepreneur or scientific innovator. If such people exist and immigration restrictions are the only effective way to keep them from perpetrating their nefarious deeds, then that could potentially be a serious rationale for restrictionism. After all, one massively harmful migrant could potentially outweigh the benefits created by a large number who make "normal" contributions to society. Ideally, we would just keep out the enormously harmful individuals, while letting "normal" migrants through. But it may be  impossible to identify the former with precision, so the only way to keep them out might be to exclude large numbers of other people, as well.

The problem of the massively harmful individual immigrant is distinct from concerns that large masses of migrants might collectively cause great harm, such as increasing crime, overburdening the welfare system, spreading bad cultural values, voting for terrible political leaders, weakening liberal democratic institutions, or exacerbating environmental degradation. These issues have already been covered in detail by both defenders and critics of migration restrictions. I myself go into them at some length in various writings, including Chapter 6 of my book Free to Move.

By contrast, I have yet to see any systematic analysis of the issue of the extraordinarily harmful individual immigrants. But the concern is an intuitively obvious one, and I see it come up fairly regularly when I give presentations on immigration-related issues. Both laypeople and experts occasionally raise it. At the very least, it deserves some serious consideration.

Are there actual examples of individual immigrants who cause great society-wide harm? There is at least one. And oh what an example it is: Adolf Hitler! In 1913, Hitler immigrated to Germany from Austria; he didn't become a German citizen until 1932. There is a plausible argument that Hitler's move to Germany was an essential prerequisite for the Nazis' rise to power, which in turn led to World War II and the Holocaust. Had the then-tiny Nazi Party that Hitler joined in 1919 remained under the uninspired leadership of its founder, Anton Drexler, it's unlikely it would ever have amounted to much of anything.

Had Hitler been forced to remain in Austria, he would never have become the leader of the Nazis, much less dictator over all of Germany. Even if he had gone on to become a fascist dictator of Austria, the resulting harm would have been far smaller, if only because Austria was a much less powerful nation.

More generally, I can see two major ways in which an individual immigrant could cause extraordinary harm. One is the Hitler Scenario: leading a political movement that perpetrates great evil when and if it comes to power.  The second is developing an enormously harmful scientific or technological innovation. If immigrants disproportionately contribute to beneficial innovations, perhaps they might also be disproportionately responsible for harmful ones. For example, an immigrant could develop an especially heinous torture device, new surveillance tech that can be used to facilitate repression, or an innovation that greatly damages the environment. Call this the Mad Scientist Scenario (though scientists who make harmful innovations usually are not actually insane!).

Both scenarios have some intuitive plausibility as rationales for immigration restrictions. If barring Austrian migration to Germany was the only way to forestall the rise of Hitler and the Nazis,  even I have to admit that's a price worth paying!

But before endorsing these theories, it's worth applying the three-part test I developed for assessing other consequentialist rationales for migration restrictions, in Free to Move:

  1. Consider how big the problem is. If the answer is that it's nonexistent or greatly overblown, restrictions aren't justified.
  2. If the problem is real, is there a "keyhole solution" that can address it without actually barring migrants?
  3. If the problem is real, and there is no effective keyhole solution, can we address the issue by tapping some of the vast wealth created by migration?

Assessed in this way, both the Hitler and Mad Scientist scenarios start to look less impressive.

Under the first step, how you assess the Mad Scientist scenario largely depends on your views about technological innovation more generally. If—like me—you think it's generally beneficial, despite the occasional harmful invention, then you will be inclined to look favorably on the large increase in innovation caused by migration. Harmful innovations are the price we pay for beneficial ones. And there is, of course, no reason to believe that immigrant innovators are disproportionately likely to make harmful innovations relative to beneficial ones (though they make more of both, relative to natives).

If, on the other hand, you are a techno-pessimist, then you are likely to take a different view. But, in that event, you should also advocate for severe restrictions on innovation by native-born citizens, as well. You may even want to deport some of the more talented native-born scientists and inventors to places where they are less likely to succeed!

The Hitler Scenario strikes me as more significant. The only way to dismiss it outright is if you think political history is ultimately determined by structural factors, and individual leaders play little role. On this view, if Hitler had stayed in Austria, the Nazis (or some other similar right-wing nationalist party) would have come to power in Germany anyway, and pursued largely the same policies as Hitler did. While structural factors certainly matter, I think individual leaders also can make a big difference, at least sometimes.

Still, several factors suggest the risk here is small. Indeed, it's hard to think of any case where an immigrant has successfully led an illiberal authoritarian movement to power, other than Hitler (though of course that one case was hugely important). If the Hitler Scenario were a significant systematic risk, we should expect to see more cases of its coming to pass, or at least more near-misses.

One factor that makes the scenario unlikely is that immigrants generally participate in politics less than native-born citizens and have fewer of the kinds of connections needed to rise to power within the political system (see Chapter 6 of Free to Move for citations to relevant data). Another is that illiberal political movements often have ethno-nationalist ideologies that privilege the majority ethnic or cultural group as the "true" owners and rulers of the land. For obvious, reasons, an immigrant is unlikely to be a plausible leader of such a movement.

Here, Hitler is actually the exception that reinforces the rule. As a German-speaking Austrian, Hitler could present himself as a member of essentially the same ethnic, linguistic, and racial group as native-born German nationalists. But that's a relatively rare situation.

If you worry that immigrants might lead a successful fascist movement, the most plausible candidates are those who share a common ethnicity race, language or culture with the natives. For the United States, that probably means a special focus on white immigrants from anglophone Canada, the UK, Australia, and New Zealand.  Ironically, of course, immigration restrictionists usually most want to keep out immigrants from more divergent backgrounds and cultures.

Could an immigrant instead lead a left-wing socialist authoritarian movement? Such groups are often more cosmopolitan in orientation than nationalists, and thereby more open to following immigrant leaders. This possibility can't be ruled out. But I cannot find a single case where an immigrant actually played a decisive role in bringing such a movement to power. The closest example is Che Guevara's role in Castro's communist regime in Cuba (Che moved to Cuba from his native Argentina).

Che Guevara did indeed become a high-ranking regime functionary under Castro, and was responsible for many horrific atrocities. But it is highly likely that the Cuban communists would have seized power even without Che's assistance, and would have pursued essentially the same policies after coming to power, even if Che had never set foot in Cuba. The Batista government would have done well to keep Che out. But it's hard to argue that he had the same kind of massive impact on Cuba as Hitler had in Germany. And, as with Hitler in Germany, Che's rise to power in communist Cuba was likely assisted by the fact that he came from a nation that spoke the same language and had a relatively similar culture.

Finally, it's worth noting that the risk that an immigrant might lead a triumphant harmful political movement must be balanced against the potential benefit of one of them playing a decisive role in leading a movement that does great good. The latter is highly unlikely, for much the same reasons as the former is. But if we are going to consider one scenario, the other deserves consideration, and should be weighed against it. One of the immigrants we keep out in hopes of barring the next Hitler, could actually have been the next Martin Luther King.

In sum, the risk of a Hitler Scenario is very low, but not zero. But even that relatively low risk can be mitigated by keyhole solutions. Most obviously, societies can adopt a variety of constitutional and other safeguards that block illiberal authoritarian movements from coming to power in the first place. Given the risks posed by native-born authoritarians, such safeguards are necessary even if the society has little or no immigration.

And relying on these tools allows a nation to protect against authoritarianism without losing the immense economic and other benefits of free migration. We might not be able preemptively keep out would-be Hitlers and Che Guevaras. But we can do much to ensure they never come to power.

Relevant safeguards include classic strategies like constitutional limits on government power, political decentralization, strong judicial review, and others. In extreme cases, governments might even bar illiberal, anti-democratic parties from contesting elections, as West Germany did with both the Nazis and communists for many years after World War II. This kind of approach carries risks of its own (incumbent political leaders can abuse it to suppress other opposition, as well). But the same is true of migration restrictions, which pose a grave threat to a variety of liberal values, including the liberty of natives.

If you worry about the Mad Scientist Scenario, it too might have possible keyhole solutions. Rather than trying to bar immigrants who might become scientists or entrepreneurs, the government could try to restrict especially dangerous lines of research. Obviously, this depends on the government's ability to predict which types of research pose a threat. But using immigration restrictions to suppress harmful innovation also requires the government to have substantial predictive abilities (figuring out which potential migrants—or groups of migrants—are likely to pose a threat), unless you want to go so far as just barring migration entirely.

In addition to keyhole solutions, the vast new wealth created by free migration can also help mitigate the danger posed by would-be immigrant authoritarians. Much social science research finds that high-income countries are more likely to become democratic—and stay that way. In that respect, the new wealth created by migration can strengthen democratic institutions even if it is not deliberately used for that purpose. And it can help protect against both native-born and immigrant authoritarians.

Situations where the Hitler and Mad Scientist scenarios can justify large-scale immigration restrictions are theoretically possible. But, in practice, it seems like they are extraordinarily rare, if they exist at all.

The Hitler and Mad Scientist scenarios are not the only possible ways an individual immigrant can cause great societal harm. They are just the most obvious. We can certainly imagine others. The best-known, perhaps, is the risk that an individual immigrant might organize a massive terrorist attack, like 9/11. This scenario, however, is subject to most of the same counterarguments as claims that groups of immigrants might increase terrorism (I discussed the issue here). In addition, even a large terrorist attack is far less likely to decisively damage societal institutions than the rise to power of authoritarians or a harmful innovation with large society-wide effects. In all of modern history so far, there has never been a terrorist attack by an immigrant that did large-scale systemic damage to liberal democratic institutions (though there certainly have been some that caused substantial loss of life, as is also true of those perpetrated by natives). Authoritarian terrorist movements led by natives have often had greater impact, perhaps for the same reasons that other effective political movements are almost always led by natives.

There is an inexhaustible list of other scenarios we can come up with where extraordinary individuals cause great harm. But each of them should be put through the same three-part analysis before it can be used to justify immigration restrictions. And if you can't think of even one real-world example where this kind of disaster actually happened—out of hundreds of millions of immigrants over the last two centuries—that's a pretty strong sign it's highly unlikely to be a real issue. By contrast, there are hundreds, probably even thousands, of examples where individual immigrants made decisive contributions to some massively beneficial innovation.