The most popular argument against illegal immigration is probably that breaking the law is wrong.  At least since the Nazis, though, virtually no one believes that breaking the law is always wrong.  Instead, we all recognize circumstances under which being a scofflaw is morally acceptable.  Law professor Ilya Somin elegantly explains the three leading theories of justified law-breaking in The Washington Post – and applies them to illegal immigration.

Let’s consider them in order of popularity.

1. Strong presumption.  The most popular theory is probably that breaking the law is only justified under desperate circumstances.  As Ilya explains:

Some believe that there is a very strong presumption that can only be
overcome by extremely powerful countervailing considerations. For
example, perhaps southern blacks were justified in violating Jim Crow
laws in the days of segregation, because of the severe harm that those
laws inflicted on them. But ordinary Americans today are not justified
in violating laws that harm them in more modest ways.

This story has an obvious problem: Most of its explicit proponents routinely break laws for trivial reasons.  Just look at the fraction of drivers who occasionally exceed the speed limit – and picture how they’d react if a passenger morally condemned them for driving 56 mph in a 55 mph zone.  

In any case, as one of my favorite challenges suggests, illegal immigration easily overcomes even a strong presumption in favor of obeying the law:

If anything is enough to overcome the strong presumption, it surely is a
situation where obedience forces you and your family into life-long
poverty and oppression that you did nothing to deserve, and violation of
the law does not in itself harm anyone. The strong presumption theory
might still condemn illegal immigrants who come from advanced liberal
democracies, such as Canada or Britain. Life in these countries is at
worst only modestly less happy and free than in the United States. But
the vast majority of illegal immigrants are fleeing far worse condition –
often even worse conditions than African-Americans endured in the Jim
Crow era.

2. Weak presumption.  The theory most consistent with people’s concrete moral reasoning is that legality only marginally tips the scales of righteousness.  Ilya:

Many people implicitly assume that there is only a relatively weak moral
presumption in favor of obeying the law. If obeying a law is
inconvenient and violating it is unlikely to harm anyone, they believe
that violation is morally justified. That explains why most people
believe it is morally permissible to violate the speed limit laws, so
long as you don’t drive so fast as to seriously endanger other drivers
and pedestrians. Strict compliance with the speed limit would be
annoying and inconvenient, and make it harder for us to get to our
appointments on time. Ditto for violations of various federal
regulations that ordinary citizens and small businesses routinely run
afoul of. Obeying all of these laws to the letter would be costly and
inconvenient, and most people believe it is all right to violate them in
cases where there is no significant harm to others.

Under the weak presumption, the propriety of illegal immigration is a true no-brainer:

[I]llegal immigrants have a much stronger case for violating immigration
laws than native-born citizens do for their routine violations of the
speed limit and various petty federal regulations. For most illegal
immigrants, obeying the law would harm them a lot more profoundly than
merely making it harder to get to work on time. It would consign them to lives of poverty and oppression in the Third World, a harsh fate imposed on them through no fault of their own, merely because they were born on the wrong side of a line on the map.

3. No presumption.  Ilya closes with the decidedly unpopular view that legality is morally irrelevant:

Finally, it is worth noting that scholars such as A. John Simmons and Michael Huemer argue
that there is no presumption in favoring of an obligation to obey the
law at all. They hold that a moral obligation to obey a law requires
something beyond merely the fact that it was enacted by a government,
even a democratically elected one.

Part of me wishes that Ilya spent more time on the latter theory.  After all, it’s true.  But Ilya made the right choice.  Why struggle to sell Washington Post readers on a new philosophy of law when their pre-existing philosophies lead to the same conclusion?