militate (v.)

1620s, of persons, "to serve as a soldier" (now rare), from Latin militatum, past participle of militare "serve as a soldier," from miles "soldier" (see military (adj.)). The sense developed via "to be in conflict with, be at variance" to "be evidence" for or against, "have weight or force in determining anything" (1640s). Related: Militated; militating; militation.