The case of the day is Hernández v. Mesa (S. Ct. 2017). Hernández is one of the cases the Supreme Court decided on the last day of its just-concluded Term. Several of the decisions were highly interesting; none of them was a private international law case; but Hernandez is quite literally a cross-border case, so I bring it to your attention here.

Sergio Hernández, a Mexican teenager, was hanging out with his friends in the cement culvert on the Rio Grande that separates El Paso, Texas, from Ciudad Juárez, Chihuahua. The international border runs right down the middle of the culvert. Hernández was on the US side of the border, and when Jesus Mesa Jr., a border patrol officer, arrived and arrested one of his friends on the US side, Hernández ran down the side of the culvert and across to the Mexican side. Mesa, standing on the US side of the border, fired two shots and killed Hernández, who was unarmed. Hernández’s parents sued Mesa, arguing, on a Bivens theory,¹Bivens is the case that created a non-statutory action for certain constitutional torts against public officers. that Mesa had violated Hernández’s Fourth and Fifth Amendment rights.

The black-letter law is that foreigners outside of the United States do not have rights under the Fourth Amendment, which protects the right against unreasonable search and seizure. There was some question whether a person in Hernández’s position has rights under the Fifth Amendment, which protects the right to due process of law; but the lower courts agreed that Mesa was entitled to qualified immunity because it was not clear that Hernández had Fifth Amendment rights. The situation would, of course, have been very different if Hernández had been on the US side of the border when the shooting occurred.

The Court, in a per curiam decision, vacated and remanded the case for further consideration on both the Fourth and Fifth Amendment issues, so we don’t know how the case will ultimately come out. Justice Thomas had a short dissenting opinion suggesting that the Court should have rejected the claims outright. But Justice Breyer had a much more interesting dissent, in which he focused on the strangeness of making the case turn on the imaginary surveyor’s line that marks the legal boundary between the United States and Mexico. He pointed out that the idea of a Euclidean line, with length but no breadth, as a border is modern; and that in the past, people thought about a river, a mountain range, or a similar geographical feature, with breadth as well as length, as the border. In practice, the border posts for the two countries are set back from the actual border, and the culvert at issue in the case was a kind of no-man’s land, what Justice Breyer calls a limitrophe area, built by a US/Mexico border commission. According to Justice Breyer, there are both international law and US law reasons to give special treatment to such an area.

I think there is a lot to be said for Justice Breyer’s way of thinking. Can I stretch a bit and compare my thought on this to what I’ve written previously about the leap second? As you probably know, a second, traditionally, was defined as 1/86,400 of a day (there are 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute, and 60 x 60 x 24 is 86,400). But in recent decades our timekeeping precision has gotten so good that we now define the second as “the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.” Because the speed of the rotation of the earth is not a constant but the duration of the newly defined second is, there is a drift between the time that we measure based on the length of a day and the time that we measure based on the atomic clock, necessitating a leap second every few years to keep the two in sync. Some folks have called for the abolition of the leap second, but I reject that idea, because it seems to me to ignore what timekeeping is for, at least for everyday human life: it’s for counting days, months, and years, all of which have to do with the sun and the moon. So there are some technical and scientific purposes for which exception precision in timekeeping is needed, but we shouldn’t put the cart before the horse and pretend that that definition of time is the relevant definition of time for our ordinary human purposes.

The point with the boundary is similar. There obviously are some respects in which it’s very important to have as precise a border as possible. Maybe this case illustrates one such respect, or maybe not. But leaving the specifics of this case aside, we shouldn’t imagine that the ultra-precise definition of the border is the only definition or even the most useful or relevant definition for most purposes, including perhaps many legal purposes. It is more meaningful to say that the Rio Grande river is the boundary, even if that means accepting some ambiguity about the legal effect of events that happen in the fuzzy area within the width of the river itself.

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  Bivens is the case that created a non-statutory action for certain constitutional torts against public officers.