Is a defendant acting "under the color of state law" a violation of Section 1983 of the Federal Civil Rights Act?

defendant is a 'person' acting 'under the color of state law,' and (b) that the defendant caused the plaintiff to be deprived of a federal right. Back v. Hastings On Hudson Union Free Sch. Dist., 365 F.3d 107, 122 (2d Cir. 2004). To act under color of state law or authority for purposes of Section 1983, the defendant must have "exercised power possessed by virtue of state law and made possible only because the wrongdoer is clothed with the authority of state law." West v. Atkins, 487 U.S. 42, 49 (1988) (internal quotation marks omitted) (emphasis added). "[G]enerally, a public employee acts under color of state law while acting in his official capacity or while exercising his responsibilities pursuant to state law." Id. at 50.