The Green Lantern Corps in DC Comics has had countless heroes protect the cosmos with their power rings, a duty that Batman turned down on one occasion. While Gotham City has a clear need for a hero like Batman, there have been other times when his heroic colleagues called upon him to take on the power of a Green Lantern. During his time as the weary leader of the Justice League International, Batman fielded immense tension between the Green Lantern, Guy Gardner, and the rest of the team, consisting of Black Canary, Martian Manhunter, Mister Miracle, Captain Marvel, Oberon, Dr. Fate, Blue Beetle, Dr. Light, and Booster Gold. It was under these circumstances that he nearly became a Green Lantern.
In Justice League #2 from Keith Giffen, J.M. DeMatteis, Kevin Maguire, and Al Gordon, Blue Beetle suggests that Batman become a Green Lantern to save the rest of the team from Guy Gardner's obnoxious antics. Batman replies, "[the power ring] would only get in my way," to which Blue Beetle responds, "Yeah... besides, who'd ever buy a super-hero called the 'Green Batman' ? I mean, that's almost as dumb as–" "The Blue Beetle?" says Batman.
This hilarious exchange between one of the most lighthearted members of the JLI and its morose leader is a pointed jab at not only Batman's place in the DC Universe, but also Golden Age superheroes. Batman's nomination for the Green Lantern role by Blue Beetle is telling of his competency as a hero, a quality that this particular iteration of the Justice League was lacking. Moreover, Blue Beetle's awareness that superheroes exist as a genre of media meant to be consumed by the public is reflective of the JLI's satirical bent as a team. By bringing up the simplicity of Batman's name, Blue Beetle hits at one of the reasons why the Dark Knight has been such a popular character for decades.
Both debuting in 1939, Blue Beetle and Batman are from the earliest age of superhero comics, and while Batman as a name has a certain timeless quality to it, the same cannot be said for Blue Beetle. Even as the character was popularized with the advent of its second reincarnation, Ted Kord, it's clear that the character will never quite have the same air of mystery as characters like Batman. By becoming the "Green Batman," Batman would lose all the edginess that has made him one of pop culture's most enduring figures.
While Green Lanterns have come in every shape and form across the universe, it is undeniably funny to imagine Batman flying around with a power ring in his bat-themed cape and cowl. The tension between Guy Gardner and the rest of the JLI team presented every opportunity for Batman to become a better Green Lantern than him, and his decision to stick with his Dark Knight persona is indicative of his own self-control as a character. And while he has flirted with harnessing the power of a Green Lantern several times of the years, it is a good thing that Batman has never fully abandoned the identity that made him so iconic.