River Border
River Border
[Ponytail and Megan are standing on a grassy riverbank, with the nearby part of the river shown above their heads. They are looking towards the river and Ponytail is gesturing at the river with her hand.] Ponytail: This is a cool spot. Ponytail: The Missouri-Nebraska state line follows this river. If the river's path changes gradually, the border moves with it.
[A map is shown beneath the text spoken by Ponytail (off-panel). The map includes a bendy river shown in gray which is snaking its way from the left part of the panel down to the bottom. A dotted line indicates the old path of the river. It follows the gray river most of the way, but towards the bottom, this line moves away from the current river extending to north-east, including a large chunk of land that the river used to encompass previously. Two arrows point to the gray section of the river with the dotted line, and another arrow points to the section of the dotted line not following the gray section. Both are labeled. On each side of the dotted arc, where it is farthest from the gray part of the river the state names are labeled, so the text follows the direction of the river (almost north to south here).] Ponytail (narrating): But when it abruptly changes course, the border stays behind. Ponytail (narrating): This is a spot where that happened. We're on the Missouri side, but we're in Nebraska. River Old riverbed Nebraska Missouri
[In a frame-less panel (with no background) Ponytail has turned to look at Megan who is holding a hand to her chin.] Megan: Wow. Megan: So... Megan: We can commit all the crimes we want here and the cops can't do a thing!
[Megan runs away from Ponytail while she is holding her arm up in the air with a finger extended up.] Ponytail: What? No. Why would you even think that? Megan: I'm going to cut a pizza into a spiral! Ponytail: That's not even illegal! Megan: Crimes!

Ponytail explains to Megan that the Missouri-Nebraska state border is based on the Missouri River they are watching. And because the path of rivers mostly only changes slowly, these borders are typically adopted to that changes. But then she explains that the river once had changed abruptly by a meander cutoff and the border didn't move with it. That means that they are on a part of the Missouri side of the river that in fact belongs to Nebraska.
It then occurred to Megan that she could break the law in this area because she is under the mistaken impression that she is in Nebraska but the police can't reach her over the river and Missourian cops actually don't have jurisdiction. In fact, there are no bridges linking it to Nebraska so police would have to go through Missouri in order to get to that part of Nebraska.
It should be noted that there are real-world examples of strange border interactions that either create legal loopholes or make law enforcement difficult.  A famous example, in the US, is a section of Yellowstone National Park that crosses over the Idaho border. An article in the Georgetown Law Review noted that, since the Park is a federal district, and juries must be selected from people living in the same state and federal district as the crime, the only qualified jurors would have to live in the Idaho section of the park, but that section has no permanent residents. In theory, then, any crimes committed on this patch of land could not be prosecuted. How this would work out in real life remains questionable, as there are no records of anyone being arrested for a crime in that region, but the law seems to have inadvertently created a zone in which laws cannot be enforced.  Similarly, Bir Tawil , a region along the border between Egypt and Sudan, is claimed by neither country as a result of the Halaib Triangle border dispute, and thus crimes committed in the area would be unlikely to be prosecuted.  Megan seems to mistakenly think something similar is in effect any time a state's border briefly crosses a river.
The final panel shows Megan saying she's going to cut a pizza into a spiral, which while unconventional is by no means illegal, and she runs off to commit more things she calls crimes, likely similar acts to cutting a pizza in an uncommon way.
In the title text, Randall claims/hypothesizes the disputed region is probably considered like the high seas , suggesting the pizza case would then fall under maritime law . "Pieracy" is a portmanteau of pie (another name for a pizza) and "piracy"; and pizzas are frequently made with marinara sauce, so "Maritime" law is rendered "Marinaritime". This is most likely a reference to The Martian , in which it was noted that Mars is technically international waters as well.
The region mentioned in the comic can be seen here at Google maps and is known as McKissick Island . In 1904, the U.S. Supreme Court confirmed in Missouri v. Nebraska that a sudden change of a river's course does not change any border. See: Missouri v. Nebraska, 196 U.S. 23 (1904) .
This strip is alluding to the concepts of 'accretion' and 'avulsion' in boundary law.
Accretion is the gradual change of the location of a river or stream by erosion or addition of sediment through natural river processes. According to common law in the United States and elsewhere, if a river or stream location changes gradually, then the boundary line moves with the stream. In cases of pure accretion, it is possible for a parcel of land to be entirely eroded away on one side of a river, and have material be added to the opposite side of the river. In such cases, one property owner could lose all their land.
An avulsion is a sudden change in the location of a river or stream, often due to flooding. In times of flood, a river can cut a new channel through surrounding land, which can create islands and oxbow lakes. According to common law, an avulsive change will not change the boundary of the land, as it is likely that the property is unchanged except for the new channel.
In the real world, however, river systems undergo both accretion and avulsion multiple times over a period of time. This makes the determination of property lines along riverine boundaries one of the most complicated aspects of boundary surveying. An examination of a river boundary will require in-depth research of the local history of the river, including reviewing deeds, government survey plats, private survey maps, aerial photos taken over time, local landowners recollections, and local lore. In situations where there is disagreement over whether an avulsive or accretive change happened, landowners may have to go to court for a suit to quiet title.
Further in-depth reading may be found in the US Bureau of Land Management's 2009 Manual of Surveying Instructions, Chapter 8, specifically pages 197-205. (See: PDF (37.7 MByte) .)
Often, borders defined by a river actually change. There are three methods to define a border:
The Mexican-US-Border that follows the Rio Grande is one of the most prominent examples of an international border that needs meticulous regulation. Thus, the International Boundary and Water Commission was created. This commission was involved when the two nations rectified the course of the river, ceding equal amounts of land to each other. The Canada-US-Border is overseen by a similar commission. There is also a strange section on the border to Canada, which Randall mentions in this comic: 1902: State Borders .
The border between Delaware and New Jersey veers from the median and talweg methods such that Delaware's border includes all the way to the New Jersey shore where the Delaware River is within what is known as the Twelve-Mile Circle .
One of the causes of the Iran-Iraq War was the dispute on shipping rights on the Shatt-el Arab river , and because the border was defined as the low water mark at the eastern side of that river, Iranian shipping was severely restricted. So the Shah of Persia announced to ignore the 1937 treaty on shipping rights, saying that most riverine borders all around the world are defined by the talweg.
Between Switzerland and Italy, the border is, at most locations, defined by the actual drainage divide . Because the Theodul Glacier between Zermatt (Switzerland) and Breuil-Cervinia (Italy) is slowly melting, the drainage divide moves southwards, thus slowly enlarging the Swiss territory.
Most other national borders in Europe are defined today as fiat borders instead of following natural landmarks like rivers. If a river changes course now, the depicted situation would occur; however, most larger rivers have been rectified more than a century ago and thus don't change course often.
[Ponytail and Megan are standing on a grassy riverbank, with the nearby part of the river shown above their heads. They are looking towards the river and Ponytail is gesturing at the river with her hand.] Ponytail: This is a cool spot. Ponytail: The Missouri-Nebraska state line follows this river. If the river's path changes gradually, the border moves with it.
[A map is shown beneath the text spoken by Ponytail (off-panel). The map includes a bendy river shown in gray which is snaking its way from the left part of the panel down to the bottom. A dotted line indicates the old path of the river. It follows the gray river most of the way, but towards the bottom, this line moves away from the current river extending to north-east, including a large chunk of land that the river used to encompass previously. Two arrows point to the gray section of the river with the dotted line, and another arrow points to the section of the dotted line not following the gray section. Both are labeled. On each side of the dotted arc, where it is farthest from the gray part of the river the state names are labeled, so the text follows the direction of the river (almost north to south here).] Ponytail (narrating): But when it abruptly changes course, the border stays behind. Ponytail (narrating): This is a spot where that happened. We're on the Missouri side, but we're in Nebraska. River Old riverbed Nebraska Missouri
[In a frame-less panel (with no background) Ponytail has turned to look at Megan who is holding a hand to her chin.] Megan: Wow. Megan: So... Megan: We can commit all the crimes we want here and the cops can't do a thing!
[Megan runs away from Ponytail while she is holding her arm up in the air with a finger extended up.] Ponytail: What? No. Why would you even think that? Megan: I'm going to cut a pizza into a spiral! Ponytail: That's not even illegal! Megan: Crimes!
