I am on OL's side overall in this whole mess, placing the lions share of the blame for the debacle on Nabu's own actions making himself untenable as a partner, followed by the League's inactions and idiot ball holding, followed distantly by Wally having agreed to look for a new host, and then breaking that promise and putting a sentient person on a shelf. But Wally is a minor in the care and supervisions of others, so most of his fault here I have folded into the League responsibility and negligence. None of the setup for this was OL's responsibility. Honestly neither was dealing with the aftermath, but he rightly stepped up once something started smelling rotten in Denmark and the people who should have been responsible for fixing it became part of the problem.
Agreed - including the small amount of blame on OL implied by 'lion's share' instead of 'all' with regards to the blame placed on Nabu.
Also, Wallace may have actually been looking for partner-mages - he learned alchemy from
somewhere, after all, so if nothing else he's clearly been investigating magic, if not just outright learning it from someone.
Once Nabu got voted an actual member of the Justice League without Zatanna and others in the know being sat down and told that no, he is not an actual voting member, and this is a story for the public to keep an eye on Giovanni's body and prevent a public panic, treating them as compromised was absolutely the right thing to do. After Wonder Woman did not understand why 'Fate' was not released from the suppression chains when that was an unpresendented chance to force a release while Nabu was contained and unable to escape, instead letting him loose in the world was unbelievable.
As a point of note - Nabu was a full voting member of the Justice League. He was not, 'Publicly a Justice League member but privately on probation for his ongoing enslavement' - he was able to vote to keep OL out, for instance.
But OL has been building an echo chamber here, only bring in people into the know that were explicitly, specifically beholden to him, and owed him. Zatanna, desperate to get her father back. Jade, helped her go legit, including cushy job and character reference. Siskin, literal owes OL his existence. Adom, was in Giovanni's shoes for a long time before OL freed him, and also singlehandedly massacred a small army that attacked his homeland. John, made him more mainstream and seem less of a White Albatross. Also handed him the reigns of unfathomable magical power. People that would have felt beholden to him regardless of the cause.
It is true that OL only brought in people to the fight who he absolutely trusted to agree with him...
...except Cornwall Boy, who was too useful to ignore.
And this is important too: The Ghost of Marrack Past agreed with OL. Even if you say that Alan wouldn't speak up for what is Right or did not understand the full scope of what was going on... Even if you say that Adom would not disagree - respectfully - with OL should Adom think it appropriate, as he desires his own advisors to do with his decisions... That's at least one voice who made an impromptu speech about how Nabu Is Wrong, not just in this specific case where the details might be warped by perspective, but the
very idea of what he is doing is wrong.
There are other people he could have been involving that I think he avoided approaching not because they would not have been useful (like Zoat claimed the last time it came up) but because they might have disagreed, or agreed, but wanted a different approach.
Cornwall Boy was useful, so OL approached him - late in the process, admittedly. Now, the agreement was that if Cornwall Boy did not agree, then he would have his memories of the decision suppressed - but Cornwall Boy was absolutely allowed to ask questions, to explain his disquiet with the idea, and to get advice from The Ghost of Marrack Past.
Like the Queen of the Amazons, Wonder Woman's mother. Presumably trustworthy, and able to lay down a lot of influence and authority over Wonder Woman. Moreover, she is NOT in Nabu's orbit, and is at the heart of one of the two most magically protected nations on the planet. He could have approached her at any time. He never did. I refuse to believe she would have nothing to contribute to the effort.
Now to be clear: What I am about to say is not a morally perfect reason to avoid talking to Amazons, Hippolyta especially. But it is an emotionally impactful one, at least.
I do
not want to have to tell a mother that I think her beloved child is supporting a monster who keeps a slave in bondage by having threatened his child.
Now - for more logical, dispassionate reasons? This is a matter Paul wants to keep quiet to preserve the image of the Justice League as good, because they broadly are good. For similar reasons he was willing to compromise and keep Lex Luthor's image good,
if Lex were willing to actually do good. He won't help bad people look good, he won't help good people avoid their mistakes... But he will keep things quiet, sometimes, when he thinks that mistakes should be fixed in private for the sake of peace. Sometimes.
Queen Hippolyta is a queen... so she has less ability to exercise that option. Not no ability! But less. And to use her against Wonder Woman would carry all the same issues and more of simply talking to Diana himself - she has in a practical way cast her lot with Nabu, he wants in an emotional way to preserve the uncertainty that allows him to feel less betrayed, in a dispassionate sense to bring her in risks interaction with Nabu because she's his daily coworker and he is a magic-user and so, as John shows often, he can influence the minds and detect the information of those around him.
(Also she works with Batman, who would be more able to keep a secret - but Batman is clearly handling this terribly from his inappropriately brief and unhelpful interaction with Zatanna, and his reputation as Unbeatable God Of Secrets And Investigation is clearly false already because of the failure with Match, so maybe he's not more able to keep a secret after all?)
When he dropped off Klarion, he could have sounded out the guy in charge of all of China while they were face to face, and he admitted he owed you big. Make some comparisons to Nabu (the alien) taking over to the Durlan problem they have. Do you really think he couldn't keep it behind closed doors so the Leagues does not loose face publicly?
Paul does not, in fact, approve of how China handles superfunctionaries. He doesn't have a big problem with it, he thinks they handle things better in some ways even. But he would not want to give them the sheer power to ruin the League's ability to be trusted and thus do their overwhelmingly-good work that revealing this would allow.
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Part of the reason I argue on behalf of Paul's actions is that... Of the characters involved, I think he did act the best of them, though he was noticeably short of a reasonable ideal handling.
But at the same time... I don't have many better ideas for what to do. Even using drones and bombs - Nabu has shown the ability to interface with technology on a grand level when he worked against Oceanus. So, if the bombs are scry-warded and hidden, and they're used extremely sparingly, and they can both avoid harming Giovanni and meaningfully affect Nabu...
I feel like we're not left with any actual viable payloads. A smokescreen would harm Team Orange more than Nabu, and anything else that would actually hinder Nabu would be dangerous to Giovanni.
Paul is dealing with a really nasty hostage situation here; if he only had to kill Nabu without saving Giovanni at the same time (or even, just being allowed to
risk a medium-to-high chance of Giovanni being killed) then yeah, scry-warded bombs go boom. Sure, Nabu won't co-operate with a ritual like Klarion did (because Nabu, for all his faults, is not as stupid as Klarion) but there's options.
Just... Nabu has a hostage, and that negates most of those options.