"Gem is, I'd be appropriating structures from one of the two locations of which I am a princess and I don't think either suits."

"I will write Gem and ask if she thinks her criminal justice system suits for an impromptu war crimes trial on Ganymede for which Cam can't talk and most of the relevant evidence can't be introduced."

"You could also try Warp, who may have anticipated eventually getting ahold at whoever wrecked Vulcan."

So he writes both Gem and T'Mir.

My justice system is fine for everyday stuff but it would in fact be fairly farcical if I assigned a tribunal and told them to go try my alt.

I think Gem's would work better for this than mine; we've been relying on member states and haven't had any trouble with people who don't come with a member state. I wasn't going to advocate resurrecting anyone who destroyed Vulcan until we had something sensible in place but we don't yet.

"Great. Maybe we shouldn't have evaded having to try our Millennium alts for war crimes."

And he pulls a panel of people together to read Earth war crimes trial proceedings and invent something. Someone suggests that Elven justice should involve polling the victims on what they want, and so everyone in Valinor is asked whether they want Cam to be imprisoned. Six of them are in favor; on further investigation one is two and never heard the word before and the other five misclicked.

Do they want Gem to loan them some people or just homebrew it?

If she can spare some people they will be peppered with procedural questions!

She has people! Mîr has a justice system inspired by the American one, but very loosely - it has to be palatable for a mixed Elf/human population so sentencing is often "getting stuck in a Lórien" or fines, and also cases are not thrown out for procedural error, just whoever made the procedural error loses their job.

That makes sense. Together they can come up with something. He arranges for Ganymede to get their substantial paycheck before they hold the trial, expecting that the outcome will annoy them.

Ganymede appreciates their paycheck.

They can borrow their trial facility.

They are appreciative! 

The trial takes a week. At the end the judges publish a statement, the for-public-release portion of which reads:

Findings:

The destruction of Valinor was authorized in order to prevent the torture of persons uploaded by Melkor, the destruction of Endorë in its ongoing war, and potentially the discovery by Melkor of a way to circumvent restrictions on summoning in the absence of which he could spread his war to other dimensions.

Four hundred twelve billion, eight hundred and ninety two million, four thousand six hundred eighty three instances of upload torture ceased within one second of the destruction of Valinor. 

The war on Endorë killed one hundred twenty million, thirty two thousand, nine hundred ninety four people in the year prior to the destruction of Valinor, and ceasefires were signed between all parties the week following the destruction of Valinor. Biological weapons had been deployed in the war with the capacity to kill all members of targeted species with no survivors. Nuclear weapons were being developed by both sides with intent to deploy them.

All persons killed in the destruction of Valinor have been resurrected. Valinor was selected as the target specifically because of the resurrectibility of its citizens.

No persons killed in the destruction of Valinor were willing to testify for the prosecution. At the request of the court some agreed to testify, and stated that they opposed a prison sentence for the defendant. 

Additional evidence and considerations have been redacted for reasons of national security; for sealed trials it is not the case that public information will constitute a complete representation of the case. In this case the extensive redacted information was not decisive in the verdict but was relevant to the sentencing. The defendant is sentenced to time served.

Thank fuck. Cam's circles are taken down and he disappears into Hell.

And are their new acquaintances too mad at them?

Not especially!

Yay!! - in that case he will suggest to a few of their new members on Endorë that they write the GCP about demon-handling procedures!!

So prompted, three of them write the GCP to observe that in general GCP standards for prison conditions exceed their own and they're very pleased to be members but the gags are not compatible with local standards for prisoner rights. It sounds like the gags are a necessary safety precaution with humans, but Elves can't survive the extraction of their souls and are therefore not vulnerable to being talked out of them by a demon they summoned. Maybe Elves could serve as GCP summoners (with the added advantage of not dying of old age) and they wouldn't need to gag demons anymore?

Well, as long as the demons weren't coming into contact with any non-Elves that might be all right.

There's risk to parties other than the summoners?

Not at the point of contact, but better safe than sorry.

Maybe a binding could be designed that forbids demons from talking to humans, particularly?

Aren't there nonhuman nonElf species in their world?

Orcs are like Elves that way; Dwarves don't seem to have souls, they haven't gagged any demons and none have asked about their souls. There are a couple newly imported species (it's a long story; their stars got extinguished so the Noldor relocated them really fast and now they're in summoning range) but no reason any of them would be visiting a prison planet.

Still, maybe just a no talking to nonElves binding.

NonElves and non daeva.