How can Empire A convince Empire B that it has a planet-destroying weapon without helping Empire B to recreate it?

Question

By almost pure luck the wizards/scientists of Empire A made a gigantic breakthrough that allowed them to create a weapon able to destroy the world, i.e. the one and the only planet on which Empire A and Empire B are located. They were lucky because there was only one correct path in their discovery and endless false ones and by sheer luck they managed to choose the correct one. Otherwise, exhausting even half of possible dead ends would take about a decade of intensive well-funded research.

The wizards/scientists are sure that the weapon will destroy the whole world because they know how the weapon is supposed to work (the weapon has never been activated, as it would destroy the world). The government of Empire A has no reason to distrust its wizards/scientists on that. Empire A knows that Empire B wants to completely destroy Empire A (although it's mutual, Empire A also wants to destroy Empire B), so the weapon will allow Empire A to survive even if war goes really poorly, as Empire A will threaten to activate the weapon in that event ("We don't value the existence of this world if it will exist without us").

The problem? They need to convince the Government of Empire B that they really have this doomsday weapon. Obviously Empire A can't activate the weapon to demonstrate it in action. Of course they could just give the blueprints of the weapon to wizards/scientists of Empire B, so they would confirm that the weapon really works the way Empire A claims it works. But then it would not take Empire B long to produce the same weapon, thus foiling the plan of Empire A on eradicating Empire B. Eventually Empire B will re-discover the way to make this weapon anyway, but it will take lots of time, giving Empire A hope of being able to eradicate Empire B before its research will be completed.

P.S. The weapon is too large, complex and delicate to be sent to another planet (it must be placed on the planet that it will destroy) or even built on the planet to be destroyed. Constructing it in space or sending it to space isn't feasible either. And it can't be downscaled, neither in its size nor effect.

P.P.S In case of wizards, they use mathematics to model work of magical artifacts and their mathematical models are top-notch.

P.P.P.S Both Empires are dicatorships. For this reason if the regime of Empire A falls (whether due to war or revolution), then it's a death sentence to its elites. They will literally die.

Answer 1

Just wait for the right time

Empire A should fight their war with Empire B. If it goes badly enough that they want to abandon their chance at victory, then they should show Empire B how the weapon works.

This way, Empire A still has a chance to win, but Empire B does not.

While fighting their war, Empire A should still claim to have the weapon, but only for the demoralizing that it might have on Empire B's fighers.

Answer 2

As described after your edit this is just a doomsday device for mutual destruction.

It really doesn't matter if the other empire figures out how to make one as using it is only going to be even remotely sane if your are facing utter and complete annihilation anyway.

It is useless for conquest.

Telling them you have a doomsday weapon means they know they can figure out how to make one as they are at a similar technological level to you (or you'd relatively easily defeat them without the doomsday device). There is no practical use for this device beyond ending the conflict.

However, knowing you have such a device means it is extremely likely they will get it one day soon. They'll simply work it out or get it through espionage (there are no real secrets). As with the A-Bomb there will be scientists, engineers, politicians, and so on who believe both sides muct have this "weapon" to "ensure peace". Expect the other side to get it.

So all you really have is a device you can give them the plans for and say "look, if this war continues we're all doomed".

Unless one side becomes ruled by a crazy person in the future. Which happens.

So any peace has to be complete - a full integration of your societies in as short a time as practical. Well, that about wraps it up for your planet I guess, as that's not going to happen.

Of course eventually Empire B will re-discover the way to make this weapon anyway, but it will take lots of time, giving Empire A hope on being able to eradicate Empire B before its research will be completed.

You said a decade - that's not long.

Actually it will make Empire B likely to use a variety of strategies, dipolmatic and military and economic, to stall until they get it (probably quicker with espionage) and unless you have the military might to force a quick end you're doomed.

When exactly do you use such a weapon ? Answer - well practically never. Empire A could reduce your empire A size by half and you still won't want to destroy everything else. If they leave you with just a quarter of your empire, then you still won't want to blow everything to hell. A eight ? A sixteenth ?

They'll never push you to the point you'll commit suicide to not let them win. So it's militarily a useless piece of junk !

Long before you'd use it, you'd surrender in some way.

The enemy know this.

So you have a useless doomsday weapon. Congratulations.

Answer 3

Feed the Moles

An open declaration that Empire A has the doomsday weapon is likely to be treated with scepticism as a possible bluff. Better to let Empire B find it out for itself, and think that it is doing so covertly. Given their geopolitical rivalry, presumably Empire B has networks of spies embedded in Empire A's ranks. Most likely some of them are double-agents, or have been rumbled and are being fed false information. Empire A can use these channels to allow Empire B's moles to 'discover' secret documents in which political and military figures discuss the existence of the doomsday weapon, without revealing any crucial technical specifics. Failing that (or alongside it), Empire A can simply make sure that lots of documents of this kind are produced and circulated within the government with rather lax security, on the assumption that eventually some of them will fall into the hands of Empire B's undetected agents. Hopefully Empire B will be convinced that the weapon is real: after all, Empire A's leaders might lie to the world about having it, but why would they lie to each other behind closed doors?

Of course, espionage is a double-edged sword, and its existence has real drawbacks for Empire A. It may be that Empire B's spies have already independently verified the weapon's existence (which suits Empire A). It may be that they have also stolen the secret of its construction (which does not suit Empire A at all). At any rate, they will soon be trying very hard to acquire the latter secret, and I'm inclined to agree with other posters that they will succeed. Without knowing the details of the weapon's magical construction, I can't be sure how easy it is to limit the essential knowledge to a trusted handful of individuals, but it sounds like a major scientific/industrial undertaking, in which case it probably requires too many people to eliminate the possibility of leakage. The obvious parallel is the A-Bomb, which Soviet intelligence sussed the essential workings of in a matter of months.

Still, regardless of the long-term viability of Empire A's strategy, the question asks for suggested means of convincing Empire B that the weapon exists, and that's what I've tried to provide.

Answer 4

My Dearest Emperor B,

As befits the closest of eternal friends, I hope my messenger finds you and your lovely spouse in good health.

Thank you for your recent gift of exotic animals and slaves; they were delicious. It is my most fervent wish that you enjoy the reciprocal gift that accompanies this letter.

I include a humorous anecdote: My foolish and ignorant Generals and Wizards, whom I despise, have devised an infernal engine that they call a "Doomsday Weapon". When applied, this device will destroy both sides unwise enough to contest for mastery.

I have commanded my errant fools to prove to me that this device works as intended by destroying the Moon on Thursday the 10th. My Wizards sniveled that the device is too complex, and that the Moon lacks air for the construction job. Irrelevant -- after a few public crucifixions, the rest of the Wizards found a way, and construction is proceeding apace. Is that not what Magic is for?

As it is obvious that this engine is worthless for conquest, making both our nations even more unassailable, I merely mention the event so that you may command your artists to record the Moon's beauty before it is gone forever, and so that you may appropriately berate your own Astronomers, Generals, and Wizards.

Your eternal and magnificent friend,

Emperor A

Answer 5

Get the wizards drunk or otherwise damage their memory after they verify the weapon is functional.

Have the wizards use their magic to prove the artifact will work, and then work to damage their memory with drugs or magic or concussion or death.

Since you are threatening to destroy the world, threatening a few scientists is a minor concession. You can simply have the scientists come to the base, verify the artifact is functional, and then damage their memory.

Answer 6

Condemned prisoners

Empire B has sent a few spies to learn the secret of Cobalt-Thorium G. Unfortunately for them, they have been caught, and await execution. Luckily for them, Empire A has had a change of heart and has allowed them a chance to pore over all of the technical schematics and interview key scientists!

Unluckily for them, they will only get a chance to answer a single Yes/No question about whether the plans work, in the presence of international observers, before their meeting with the intestinal spindle. *(this is via a highly restricted choice of hand signals, to prevent any untoward outburst or covert sign)

Answer 7

You can prove that you have a doomsday weapon by enacting the Doomsday Weapon Antiproliferation treaty with empire B

To start, you must immediately disassemble the doomsday machine. There is no situation where the use of the weapon by any actor results in a favorable outcome for anyone.

Then send send the math that proves it is a doomsday weapon. Once the empire realizes the math is for a doomsday weapon they will have no use for it. Normally you wouldn't do this, since any research you give to the enemy is a loss, but since the weapon

can't either be downscaled, neither in its size nor effect.

there is nothing to be gained from this knowledge aside from that a doomsday device is possible. You should also send empire B a treaty you want signed.

DWA treaty details

The treaty will have every nation who signs this make laws to make the construction of doomsday devices, research into doomsday device technology, and the collection of materials vital to the construction of doomsday devices illegal. The treaty will detail sanctions to those who violate the treaty, either by failing to complete inspections or amassing illegal magical materials. It also includes an agreement to invade countries that have Doomsday devices or are attempting to construct doomsday devices. Also included will be regular checks for doomsday devices by impartial observers, and observers sponsored by each member of the treaty. This will be similar to nuclear inspections in real life.

Don't tell anyone the secret

You only need to tell people what materials are needed to make the device, but not how. Everyone is under the same restrictions, including your empire. Just like most people know radioactive materials are needed for nukes without knowing how to make a fusion bomb, you can do the same.

Answer 8

If the common population won't admit Covid-19 exists until people start dying from it, the government of Empire B won't believe a doomsday weapon exists either.

The answer is simple. Demonstrate the weapon on another planet. If you could make this device, then you could move to the nearest planet as well. If not, you have to make a scaled down version at least to demonstrate it. The world's governments didn't believe in the existence of nuclear bombs until Hiroshima and Nagasaki, as well.

The "many dead end paths to solution, got lucky" problem that is a barrier to inventing the doomsday device sounds like an NP problem (https://en.wikipedia.org/wiki/P_versus_NP_problem), for which a solution could be checked if it is the solution quickly but you can't solve the problem quickly. After all, how could A's inventors even tell they've got a working device themselves? In this case, let the solution check be sent to B's people, or have a few highly renowned and trustworthy people from B go to A to check the solution, but without sending the whole blueprint or the complete set of equations.

This is not a useless weapon. If war breaks out, Empire A's best possible outcome is victory, while the worst possible outcome for Empire A is a tie where A and B gets destroyed. Yes, you might think that the death of everyone on the planet is far worse than the surrender of Empire A and the death of a few Empire A elites. However, those Empire A elites are in charge of Empire A. If A surrenders, the elites die. If they turn on the doomsday device, the elites also die. There is a branch possibility where Empire B believes in the doomsday device's existence but uses it to persuade Empire A's non-elite disgruntled population (those that would never have died but would come under a new overlord if Empire A loses) to rebel, where A would need to do their best to convince their population it's in their best interests not to rebel because B would rape, kill, pillage, etc.

Back to it being not a useless weapon: it's a form of one-sided mutually assured destruction. By the way, I recommend the Three Body Problem trilogy. The second book, Dark Forest Theory, has a similar scenario of MAD being used in negotiation.

B has two options: attack A swiftly with everything before the persuasion could finish and use spies or fake news to incite rebellion etc to take the doomsday device before anyone reacts, or settle down for a long peace period because starting a war is clearly a dead end with no victory in sight while using the long peace to steal the doomsday device's secrets. On the other hand, A needs to hand the doomsday device's trigger to a seemingly insane or highly resolved emperor in order to make sure MAD is believable.

Answer 9

Empire A should announce that they have the doomsday weapon, and request a meeting. During this meeting, Empire B would send a delegation consisting of the most trusted and patriotic people, including at least one scientist/wizard who could verify the claims, given the evidence that Empire A's science division has produced.

Empire A would put all the proof inside a room or vault and invite the delegation to meet outside. B's scientist/wizard would be invited into the room to verify the claims while the rest waits outside. After B has verified the doomsday weapon exists, they would exit the room and proclaim to the delegation that the doomsday weapon is in fact real. The scientist/wizard would then be taken into custody of Empire A and kept in isolation, so they could not spill the secret, or be executed immediately depending on what Empire A is like. In any case, the scientist/wizard can not be allowed back home as they have learned the secret to the doomsday weapon.

Instead, only the delegation will return to Empire B and be able to verify that the doomsday weapon indeed exists, based on the trusted word of the scientist/wizard left behind. As these are trusted and patriotic people, Empire B will be assured that they have not been pressured to simply state that the weapon exists even if it really doesn't.

Answer 10

Dr. Strangelove, I presume?

Doomsday devices are not far-fetched. It is actually something that happened during the Cold War. It is still happening. At least one exists on Earth, and is fully functional right now (if Wikpedia and Vladimir Putin are to be believed).

Allow me to present: Dead Hand.

During the Cold War, the Soviets built a system designed to destroy all civilization, and they deliberately set it up so that it would activate automatically if it detects that Russia was about to be nuked.

Apparently it is turned off most of the time, but they keep it in working order and turn it on "during times of crisis."

The only use for a doomsday weapon is as a deterrent. All you need is to convince the other side you have one. This is actually made far easier if the enemy already knows how to build the core elements (i.e. nukes, detection hardware, automatic targeting & firing).

So: if the enemy doesn't have the tech to build one, here's what you'd do. (I'll use a nuclear weapon as an example)

1. Invite envoys from the enemy to witness a weapons demonstration.
2. Detonate a small nuke. Maybe do it over a small, abandoned town, something that shows the destruction, instead of an empty field or desert.
3. Maybe afterward, you all don protective gear and go measure the radiation. Maybe you bring a parrot or a dog or some other small animal, and let them keep it afterward so they can watch it die horribly. (Yes, this is monstrous, but no less monstrous than creating a weapon that could end all life.)
4. Tell the envoy that you've built hundreds of these, bigger, and wired them up to fire at a moment's notice if they attack you.

That's it.

Answer 11

It doesn't matter if Empire B knows how to make the weapon.

Case I - Empire B does not have the weapon

Options

1. Submit to Empire A
2. Die with the world and everything else by the weapon

Case II - Empire B DOES have the weapon

Options

1. Submit to Empire A
2. Die with the world and everything else by the weapon

Does it really matter if Empire A pushes the button or Empire B does? The choices are the same. As long as Empire A succeeds in convincing Empire B that they are serious about accepting no future where their wishes are unfulfilled, and their intention to destroy the world and everything in it if they cannot have their way, then it really doesn't matter if Empire B gets the weapon or not.

If they use it, they are dead, which is the same result as if Empire A used it. Why should Empire B go through all the work of building their own version of the weapon when they could just thumb their nose at Empire A and have them use their weapon instead? If their intention is to not submit to Empire A, everyone dies no matter what.