What is the test for liability under Section 1983 of the Civil Rights Act?

[Although] to establish personal liability in a 1983 action, it is enough to show that the official, acting under color of state law, caused the deprivation of a federal right[,].... [m]ore is required in an official-capacity action, ... for a governmental entity is liable under 1983 only when the entity itself is a moving force behind the deprivation [;] ... thus, in an official-capacity suit the entity's policy or custom must have played a part in the violation of federal law.

Kentucky v. Graham, 473 U.S. at 166, 105 S.Ct. 3099 (first emphasis in original; second and third emphases added).