The Story: "The Key Crisis of the One-Man Justice League!" by Gerry Conway, Rich Buckler, and Pablo Marcos. We open with an unholy alliance between two of the JLA's most fearsome foes, The Key and Amazo!
Amazo doesn't like being bossed around, but the Key zaps him with a ray and tells him too bad, he has plans for him...
Meanwhile, we find Zatanna waiting for Ray Palmer in a park. She confides to Ray that she believes she is losing her magic powers!
Cut to The Flash, stopping some kidnappers aboard a train. He foils them, and stops the train--all in a day's work for The Fastest Man Alive.
Except...as he starts to run away, The Flash suddenly feels a pain in his leg and quickly he realizes...he has lost his super-powers!
Simiar events befall Black Canary and The Elongated Man. And when Ralph shows up at the JLA satellite to look into it, he finds several other JLAers there, all facing the same problem.
When Zatanna mentions bringing her problem to Ray, the Flash feels hurt:
Hawkman and an off-panel Hawkgirl do some investigating, and conclude that someone is "tampering" with the normal life-span of their powers. Hawkman also concludes the most natural culprit is...Amazo!
Back at The Key's secret base, we see him undergoing another of his painful "rebirths" into a new body. Just as this happens, the JLA bursts in, and then The Key sicks Amazo on them!
Amazo, having the powers of all of them, defeats the JLAers, and then turns on The Key for manipulating him. He's about to break The Key into several smaller pieces when, suddenly, the Atom delivers a blow to Amazo's head.
Amazo then realizes he no longer has the powers he had just a few moments ago, and a one-two punch from The Flash and Black Canary's sonic cry takes him out, reducing him to a pile of junk.
The Key, whose lifespan energies were connected to Amazo's powers, can't understand why his body isn't automatically reverting to its smaller, crippled form.
Turns out Zatanna gave some of her "life-energies" to The Key:
...a nice, sweet moment for Zee, followed by a great joke.
As the JLA shoots the pile o' Amazo into space (yeah, that'll never come back to haunt them), Zatanna and The Atom discuss the fact that she started losing her powers (hinted at in JLA #190) before The Key started his plan, so what's going on?
She informs him that there is an inherent limit to her magical powers, and that she was using them so massively during her first few months as a JLAer that she finds them now diminished. The Atom assures her, even with half her powers, "You'll never be less than first class!"
Roll Call: Flash, Atom, Hawkman, Black Canary, Elongated Man, Zatanna
Notable Moments: I remember at the time, this issue being a big deal, because it didn't feature either Superman or Batman.
Considering how well this issue works, I think it proved--creatively at least--that of course you could tell a good JLA story without them. I wish that this template had been used later on, when the JLA Detroit concept kicked in.