Justice League of America (1960-) #191

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 the Flash, Black Canary, Elongated Man and the Atom himself. 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 superheroes track down and defeat Amazo, while Zatanna magically cures the Key of his affliction. In the aftermath of the battle, the 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.