2020] EIGHTH AMENDMENT PRESUMPTIVE PENUMBRAS 3
Take, for instance, a speed limit of 40 miles per hour. With respect to safety,
the difference between driving 39 miles per hour and 41 miles per hour seems
negligible,3 and yet, the consequence could be significant in terms of
receiving a fine for speeding as opposed to being able to continue driving
without being stopped.4
This seems to become increasingly true the more arbitrary the chosen
bright line might be.5 If th e 40 mile per hour spee d limit resulted from careful
study of relevant data—perhaps showing a dramatically increased likelihood
of an accident once a driver crossed the 40 mile per hour threshold on the
particular stretch of road—then the bright line of 40 miles per hour would
justify the difference in treatment of the 39 mile per hour driver and the 41
mile per hour driver.6 On the other hand, if 40 miles per hour was arbitrarily
rea, even when a statute is silent); Morissette v. United States, 342 U.S. 246, 250 (1952) (reading
a mens rea standard into a federal statute). For a deeper exploration of the presumption against
strict liability crimes and strict liability, see generally Douglas N. Husak, Varieties of Strict Liability ,
8 CANADIAN J.L. & JURIS. 189 (1995) (exploring varied types of strict liability); Arthur Leavens,
Beyond Blame—Mens Rea and Regulatory Crime, 46 U. LOUISVILLE L. REV. 1 (2007) (discussing the
drawbacks to distinguishing between blame and notice in analyzing mens rea); Stephen J. Morse,
Inevitable Mens Rea, 27 HARV. J.L. & PUB. POL’Y 51 (2003) (arguing that mens rea is an important
factor in determining culpability); Herbert L. Packer, Mens Rea and the Supreme Court, 1962 SUP.
CT. REV. 107 (providing a historical analysis of the Supreme Court’s varied approach to finding
a mens rea requirement); Frances Bowes Sayre, Public Welfare Offenses, 33 COLUM. L. REV. 55 (1933)
(arguing that an exception to mens rea can be appropriate only for a narrow set of offenses);
Kenneth W. Simons, When Is Strict Liability Just?, 87 J. CRIM. L. & CRIMINOLOGY 1075 (1997)
(examining the appropriate application of strict liability in criminal cases); Richard A.
Wasserstrom, Strict Liability in the Criminal Law, 12 STAN. L. REV. 731 (1960) (arguing that not
all strict liability statutes are irrational); and John Shepard Wiley Jr., Not Guilty by Reason of
Blamelessness: Culpability in Federal Criminal Interpretation, 85 VA. L. REV. 1021 (1999) (examining
potential theories for the Supreme Court’s implicit mens rea requirement in statutory
3. See, e.g., Letty Aarts & Ingrid van Schagen, Driving Speed and the Risk of Road Crashes: A
Review, 38 ACCIDENT ANALYSIS & PREVENTION 215, 223 (2006) (finding on average that a one
percent change in speed would lead to a two percent change in injury accidents, a three percent
change in severe injury, and a four percent change in fatal accidents); see also D.C. RICHARDS,
DEP’T FOR TRANSP., RELATIONSHIP BETWEEN SPEED AND RISK OF FATAL INJURY: PEDESTRIANS AND
CAR OCCUPANTS 6 (2010), https://nacto.org/wp-content/uploads/2015/04/relationship_
9WJD-N97D](exploring a similar concept in the United Kingdom).
4. One might argue that police might exercise their discretion not to stop motorists that
do not significantly exceed (at least by five miles per hour) the speed limit. See generally Peter W.
Liu & Thomas A. Cook, Speeding Violation Dispositions in Relation to Police Officers’ Percep tion of the
Offenders, 15 POLICING & SOC’Y 83 (2005) (exploring the use of police discretion in speeding
stops). Such an exercise of discretion mirrors the presumptive penumbral conc ept advocated for
below. See infra Part III.
5. To review an extensive literature challenging the ability of bright lines to eliminate
arbitrary results, see generally Ofer Raban, The Fallacy of Legal Certainty: Why Vague Legal Standards
May Be Better for Capitalism and Liberalism, 19 B.U. PUB. INT. L.J. 175 (2010); Alschuler, supra note
1 (same); LaFave, supra note 1 (same); and Mulroy, supra note 1 (same).
6. See generally RICHARDS, supra note 3 (summarizing such studies that could be used for
the purpose of setting speed limits); Aarts & van Schagen, supra note 3 (same).