This is the first of a two-part column. The second part will publish on Thursday.With four judges dissenting from an en banc decision that applied the single incident theory of liability under 42 U.S.C. Sec. 1983 — discussed by the U.S. Supreme Court in footnote 10 of City of Canton v. Harris, 489 U.S. 378 (1989), as a possible route for holding a local governmental entity liable under Section 1983 in cases where the plaintiff alleges (1) the defendant’s employee violated her constitutional rights and (2) the …