WARNING: The following contains spoilers for Justice League #68 and Action Comics #1035, now on sale from DC Comics.
The current Justice League roster is a uniquely powerful group -- Superman, Batman, Aquaman, Flash, Green Arrow, Black Canary, and Hawkgirl have been joined by three powerhouses in Black Adam, Hippolyta, and Naomi. It's a good thing they've been so stacked in terms of potential, as the team has already come up against galactic threats like Synmar Utopica, and threats like Darkseid and the Great Darkness are lingering in the background.
Making matters potentially worse, Justice League #68 (by Brian Michael Bendis, Scott Godlewski, Gabe Eltaeb, and Josh Reed) and Action Comics #1035 (by Phillip Kenney Johnson, Daniel Sampere, Adriano Lucas, and Dave Sharpe) sees two of their most powerful number, Superman and Naomi, more or less removed from the field.
Following the successful defeat of Synmar, the Justice League is set up for another fight against the United Order over the Phantom Zone Projector. Luckily for all parties, cooler heads prevail in Justice League #68, and a fight is prevented. As the League begins the clean-up process, Doctor Fate takes Naomi to find her parents, chatting with John Constantine inside the Tower of Fate. All of them have more or less dodged the conflict as a result, and are safe. But having seen first hand the kind of threats she could be running into as a member of the League, Naomi's parents decide they don't want to throw her "into a war zone."
As Naomi bids farewell to the League, none of the heroes seem fully aware of the predicament she's getting into, instead merely complimenting her on her good work in the battle. This might mean Naomi is more or less removed from active duty, and could even end up with a group like the Titans Academy. Given her impressive power and relative youth, it makes sense that her parents would be concerned.
Meanwhile, DC has also been slowly pushing Superman closer and closer to his Future State fate of leaving Earth in the hands of his son while the Man of Steel goes to space to face Mongul. Confronting the renegade Thao-La in Action Comics #1035, Superman swears to save her people, finally giving her the strength to break her chains as well as Mongul's control over her. The effort leaves her in a coma, healing within the Fortress of Solitude. Meanwhile, Superman elects to attack Warworld. He's aware that the Justice League can't drop everything to accompany him, and he ultimately decides against waiting for them, venturing instead with the Authority.
The League explains to Superman that leaving at this time would jeopardize the work they've been doing on Earth in concert with the world governments -- which are largely enraged at Superman already for his decision to intervene in their affairs regarding the Genesis Fragment. While the League promises the Man of Steel that he'll never fully be off the team, Superman is no longer an active member of the current roster.
This is quietly a big deal, even if the League doesn't realize it yet. They've just lost two powerful members of their ranks, in a time when conflict and chaos are spreading from the darkest corners of the DC Universe. Challenges are ahead that could prove more dangerous than anything they've encountered in the past -- and if they're splintered when the time comes, it may lead to massive destruction occurring across the entire multiverse.