VII. CUSTOM OR PRACTICE
In addition to imposing liability upon municipalities for the actions of policymakers that cause constitutional deprivations, a municipality can also be liable under § 1983 when its custom or practice causes constitutional deprivations. The Supreme Court in Monell explicitly recognized that municipalities could be liable for custom or practice:
Local governments, like every other § 1983 "person," by the very terms of the statute, may be sued for constitutional deprivations visited pursuant to governmental "custom" even though such a custom has not received formal approval through the body's official decision making channels . . . . Congress included customs and usages in § 1983 because of the pursuant and widespread discriminatory practices of state officials . . . . Although not authorized by written law, such practices of state officials could well be so permanent and well settled as to constitute a "custom or usage" with the force of law.138
In Los Angeles County, California v. Humphries,139 the Supreme Court held Monell's requirements applied to claims for prospective relief as well as claims for damages.
The language of § 1983 read in light of Monell's understanding of the legislative history explains why claims for prospective relief, like claims for money damages, fall within the scope of the "policy or custom" requirement. Nothing in the text of § 1983 suggests that the causation requirement contained in the statute should change with the form of relief sought. In fact, the text suggests the opposite when it provides that a person who meets § 1983's elements "shall be liable . . . in an action at law, suit in equity, or other proper proceeding for redress." Thus, as Monell explicitly stated, "[l]ocal governing bodies . . . can be sued directly under § 1983 for monetary, declaratory, or injunctive relief where, as here, the action that is alleged to be unconstitutional implements or executes" a policy or custom. 436 U.S., at 690 (emphasis added). Monell went on to quote this Court's statement in a 1973 case, Kenosha v. Bruno, 412 U.S. 507, 513, 93 S.Ct. 2222, 37 L.Ed.2d 109, to the effect that the Congress that enacted § 1983 did not intend the "generic word 'person'" . . . to have a bifurcated application to municipal corporations depending on the nature of the relief sought against them" 436 U.S., at 701, n. 66 (emphasis added). Monell added that "[n]othing we say today affects" this pre-Monell "conclusion." [Id.]
A. Circuit Court Treatment of Custom or Practice
The circuit courts take varying approaches to the issue of analyzing municipal liability claims arising from an alleged custom or policy, although they all recognize there are four methods of proving Monell liability based on custom or practice: (1) the existence of an illegal official policy or legislative enactment the application, (2) an official with final policymaking authority ratified the illegal conduct, (3) the existence of a constitutionally deficient training program, and (4) the existence of a custom of tolerance of or acquiescence in...
