Rule 12 Player Conduct
Section 2 Personal Fouls
Article 5 No player shall twist, turn, or pull the facemask of an opponent in any direction.
Penalty: For twisting, turning, or pulling the mask: Loss of 15 yards. A personal foul. The player may be disqualified if the action is judged by the official(s) to be of a flagrant nature.
So say the official NFL rules. Note that “flagrant” violations may receive extra penalties; even unintentional violations are penalized. The motive is obvious: the infraction can seriously hurt a player.
If you understand this penalty, you already understand two of the important principles of the field of law & economics. There are certain things we want to discourage in the interests of society, and some of these things fall within the scope of the law, broadly defined. (We’d also like to discourage other things, for example being a generally negative person, but this is outside the scope of the law.) In criminal law there must be some level of mens rea (“guilty mind”), but in civil law, the component of the law that deals with dispute resolution, mens rea is not necessary. Penalizing actions that cause harm even when performed unintentionally induces a greater level of care among people who might possibly perform the act in the future. The facemask rule was introduced in 1956. Unfortunately, little game footage survives from this period, but it’s easy to see that once players were told about the new penalty they would take greater care to avoid accidentally committing the infraction, even though it always happens within a matter of seconds, in the heat of the moment. I have yet to see a facemask violation that seemed intentional. But even unintentionally it can cause great harm to a player, so it still needs to be discouraged.
That is the first principle of law & economics you might already intuitively understand. The second is that “law” does not simply refer to legislation passed by the US Congress or its equivalents in other countries. The law in football is codified in the NFL Rulebook and enforced by the NFL, not by any government. The law at your workplace overlaps with government law, but not entirely; there is still some internal process for resolving many workplace disputes, even if it is fairly informal. It would be absurdly inefficient for government at any level to involve itself with facemask penalties or which stapler belongs to whom.
Law & economics is a broad and rich field. I don’t mean to suggest that all of its principles can be understood without delving into the literature. But it is not ivory tower stuff. Its logic applies all over the sphere of human activity. Read more here.