Justice League of America #191

THE KEY CRISIS OF THE ONE-MAN JUSTICE LEAGUE! Zatanna contacts the Atom for help when she seems to be losing her magical powers (a gradual development from previous issues), but the affliction appears to be widespread, as other JLA members on individual cases also find themselves bereft of their super-abilities, including Flash, Black Canary, Elongated Man, and The Atom. The culprit is the android Amazo, reactivated against his will by the Key, who is stealing the League members' energies for his own use and to cure the Key of his dwarf-state (suffered as a side-effect of his previous cure in issue #150). With Hawkman's aid, the super-heroes track down and defeat Amazo, while Zatanna magically cures the Key of his affliction. In the aftermath of the battle, Atom learns that Zatanna's power-loss is a separate phenomenon, caused by her overuse of her skills in previous cases, and that her powers are permanently reduced as a result.