Note: this is the third in a series of blog posts …

Thus far, I have identified one reason why we must draw lines whenever we must formulate a new legal rule or apply an existing rule to a new case: the problem of competing and conflicting values. In Part II of his essay on “Line-Drawing and Legal Education,” my colleague and friend Orin S. Kerr identifies a second reason why line-drawing is inevitable: what Kerr calls “the problem of scale.” In the words of Professor Kerr:

“Once created, legal rules typically will apply to many people over a long period of time. Every person is unique and special. But we can’t design a different law for each person. Instead, we need to come up with a general approach that will apply for many years to potentially millions of different and unknown people. The scale of law creates inevitable tradeoffs.”

In other words, as “Mister Rogers” never tired of reminding his little viewers, every person is special! Every person is different. But why is this truism relevant to the line-drawing problem? Because whatever rule you prefer for a given situation (such as traffic stops), your proposed rule needs to be simple enough for anyone to understand and easy enough for anyone to enforce. To see why, let’s return to the traffic stop example we saw in our previous post. As Professor Kerr correctly notes (footnote omitted), “the police in the United States currently make more than 50,000 traffic stops on a typical day,” and to complicate matters even further, hundreds of thousands of police officers have the legal authority to make such traffic stops. As a result, any legal rule we create for traffic stops has to account for different kinds of police officers, different kinds of vehicles and drivers, as well as the effects of so many traffic stops across different communities.

Part III of Kerr’s paper provides a third reason why line-drawing is a necessary evil–both “necessary” and”evil” in the figurative sense because line-drawing is an admission that no rule is perfect, that tradeoffs are inevitable. Specifically, imagine what would happen if we refused to draw lines. Consider traffic stops again. Imagine an absolute pro-police rule: the police can pull over any car at any time for any reason. Now, imagine an absolute anti-police rule: stops for traffic violations should never be allowed. Simply put, both of these proposed rules are too extreme because they refuse to make tradeoffs or balance the competing values of promoting the collective good (road safety) while minimizing restrictions on individual freedom (being able to drive where I want without external interference).

Can you think of any other reason why we must draw lines? In the meantime, I will proceed into Part IV of Professor Kerr’s line-drawing paper in the next day or two …