In the past, there were many false alarms in US and Soviet Union or Russia, about a nuclear attack from the other side. In a few minutes, and under great pressure, they had to decide whether to retaliate, which would bring about the end of the world as we know it, in short order. The pressure happens because, if you don't retaliate and the attack is real, in a few minutes your silos and/or government are dead, and you would not be able to retaliate anymore.

It is clear that in the future, the biggest risk of starting a devastating nuclear exchange, is by mistake.

So my question is, why not ditch all that land and air based missiles and rely on submarines. If the attack is real and the country is destroyed, the subs under the sea would still be operational for a long time, and they can surely ascertain whether their country is destroyed beyond any doubt, primarily because there would be a long time to do it.

Having satisfied themselves that the country is indeed gone, the protocol for them would be then to launch their missiles to the adversary that did it.

It seems to me, that would be mistake-proof mutually-assured-destruction deterrent, where the current schemes have a great danger of eventually failing to a mistake.

It is in the interest of both adversaries, US and Russia, to have a mistake-proof retaliatory scheme. So why, since it is in both interests, their diplomats not sit down and hash it out and shake hands and everybody breaths a big sigh of relief, while still having their nukes.

Since that is not done, and it is so simple and someone must have thought about it, there must be some flaw in my argument. What is it?

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    The United Kingdom is following that doctrine. Their whole nuclear arsenal is in form of SLBMs.
    – Philipp
    Aug 11, 2017 at 13:27
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    @Philipp: True, but this is largely a cost cutting measure; it's not motivated by a desire to avoid mistaken launches. Successive UK governments have believed that having one missile submarine operational at all times is the minimum credible nuclear deterrent. Aug 11, 2017 at 13:32
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    following your logic it is possible to get back to idea of doomsday device. E.g. US can build underground nuke or nukes with total yield of several gigatons. They all to be detonated if attack on US was real and country was destroyed. This will lead to global ecosystem collapse -- good enough retaliation.
    – lowtech
    Aug 11, 2017 at 14:46
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    So, submarines would prevent one from losing their capability over a mistake, but how would mounting them on a sub prevent missiles from being launched, initially, from the subs, which would lead to retaliation from the other sides' subs? I'm not seeing the greater fail-safe in this scenario. If a sub goes deep/silent/whatever, surfaces and has missed the "all-clear, stand down" communication, then you have a strike, in error. Seems like it's just a different set of circumstances, not actual removal of the possibility. Aug 11, 2017 at 14:58
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    Just a thought experiment (covering the missing human part): If you were a sub commander in charge of ICBMs and you learned your country was destroyed, and took the time to verify (days perhaps because you have no communication) and you are somewhat certain but not perfectly certain as to who did the attack, and your state no longer supports life, and your head of state is gone, do you fire your weapons killing millions of innocent people? After all I can't see any country having a census that would authorise a nuclear attack! No you can't count on it, (with irony:) never put off til tomorrow.
    – Quaternion
    Aug 11, 2017 at 23:15

9 Answers 9


Reasons include, but may not be limited to:

  • Cost: A missile in a land-based silo is much less expensive than the equivalent on a submarine. In the Cold War era, this resulted in more "bang for the buck". The planned response to a first strike was to launch a counterstrike on a massive scale, while the missiles from the first strike were still airborne. The larger the counterstrike, the greater the deterrent.

  • Size: For technical reasons, the missiles on a submarine are restricted in size. A land-based missile can carry a larger payload, which may permit greater range, accuracy or warhead yield.

  • Communication: If a government decides to carry out a nuclear strike right now, contacting a submarine via ELF is less than ideal, due to the low bandwidth, and the size and expense of an ELF transmitter.

  • Inter-service rivalry: Different branches of the armed forces would be reluctant to give up their nuclear weapons, and any associated funding and prestige. This is particularly the case in Russia (and previously the USSR), where the land-based strategic rocket forces are a separate service branch, distinct from the army, navy and air force.

The risk of a mistaken nuclear launch was considered an acceptable price to pay for these advantages -- which may be insane, but the same can be said of many other decisions regarding nuclear weapons.

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    In this case, bang for the buck is literally about "bang for the buck".
    – user
    Aug 11, 2017 at 13:52
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    I'm not sure your cost point is really valid. Sure, submarines are more expensive than silos but they're cheaper than having both. So a country that had submarines and silos could indeed save money by getting rid of the silos. Sure, they could save even more money by getting rid of the submarines instead, but then the enemy would know where all your nukes were, all the time. Aug 11, 2017 at 21:34
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    @DavidRicherby Granted, the U.S. and Russia already do a pretty decent job of tracking each other's (and everyone else's) submarines, too. And to get the same level of possible retaliation, you'd need to build (many) more submarines, so the cost part is indeed an issue.
    – reirab
    Aug 11, 2017 at 23:08
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    I would add one more: Risk. Having everything be in submarines is to a certain extent putting all your eggs in one basket. If somehow the enemy finds a counter to SLBM then all you're nukes are neutralized. Aug 13, 2017 at 2:12
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    @DavidRicherby: If you want a deterrent at minimum cost, submarines are an effective choice. This is why all of the UK's nuclear weapons are submarine-based. OTOH if you want the capability for unimaginably massive retaliation, as the USA and USSR did during the Cold War, it's cheaper to implement using a mix of submarines, land-based missiles and aircraft than submarines alone. Aug 14, 2017 at 8:21

A submarine with nuclear missiles surfaces. It cannot reach its headquarters. There are "enemy" ships in the area that are heading towards it, including another submarine. So it can't just go back under the water safely. And even if it could, it can't communicate or launch while under water (it may actually be able to launch from a small distance under water but assume that it will be beyond that).

If the submarine does nothing and there is a nuclear war that already started, then the enemy ships will probably be able to destroy it. It is convinced that the choice is between launching its missiles now or not launching them at all if there is an active war. So your "long time" has gone down to mere minutes to make the decision.

In your proposed system, the submarine would almost have to allow itself to be destroyed in that situation. Because it's possible that this is not part of a nuclear war but just a series of bad events. But its missiles would be lost if it were a war.

So to launch a successful attack, the first thing that you would do is to send your navy to destroy all the submarines. You don't have to attack the enemy country itself at all. Just destroy the deployed submarines. The more that you destroy, the more resources you can concentrate on the remaining ones. So long as the submarines' country doesn't know that you are sinking them, you haven't shown them an act of war yet. They don't even know they are under attack. Once you destroy those at sea, use nukes or even conventional bombing runs to destroy the ones at harbor.

No mutual assured destruction (MAD). You just destroyed the enemy country without them getting a missile in the air. Why haven't countries done this? In the current system, there are still two more legs of the triad. Even if successful, you haven't eliminated the threat. And if not successful, you've triggered MAD.

One counteragent to this is to make the original scenario more paranoid. When the submarine faces the use 'em or lose 'em scenario, it uses its missiles. But now, if you can create that situation, you can start a nuclear war.


Who would want to start a nuclear war? Well, what if you are a relatively small terrorist organization in the middle east. You know that you can't defeat a nuclear power like the United States, Russia, or China. But what if you could start a war among them? The kafir would kill each other and stop meddling in your business. Some may tell you that radiation and nuclear winter will kill off people who aren't targeted by the bombs, like you. But you don't believe them. Just more kafir lies.

You compromise the Russian or Chinese intelligence agency and use it to gather information about the United States' protocols. All you really need is enough information to trigger them. You want the submarine to go underwater for a period where it looks like there might be problems. Give them the entire period under water to worry. Then when they are scheduled to resurface, cut their lines of communication. Create provocations that put ships they'll regard as enemies in their area.

Last Resort

The television show Last Resort had a similar scheme. It was foiled because the surfacing submarine wasn't worried enough. Their communications were partially subverted, but they chose not to believe them. But even there, it was a close thing. A captain who had a better relationship with the person subverting the communications might well have launched. Several of the officers thought that they should.

That of course was fiction. But it was intended as a realistic possibility.


The current nuclear triad means that we don't have to rely on any one agent. Even if an enemy destroyed all our submarines, we can still send bombers or fire ICBMs (Inter-Continental Ballistic Missiles). Attacks that work well against submarines may be useless against an ICBM.

With just the submarines, to match the current deterrent, the submarines would have to be more aggressive. Which gets us right back to the original problem of making a decision with insufficient data. Only we've moved that decision from the capital, which has as much data as possible, to a submarine that has been out of contact for days.

I also think that you overestimate the concern of a false launch. If there is one unexplained thing that might be a missile, you don't have to respond immediately or even before it lands. Even if it takes out one or even two launch bases, that leaves the rest of the land and air based arsenals. Beyond that, even if you lost the entire land and air based arsenals, you still have submarines.

If you scramble your bombers, they are in the air and can be called back. While in the air, they aren't that subject to attack via nuclear missile. You can delay the ICBM launch until the last moment. And you still have the submarines. So you have the option to not respond irreversibly.

With just submarines, you have less of a margin of error. Instead of watching out for a nuclear attack, the real danger is an attack on the submarines. They operate remotely and spend long periods out of contact. So losses aren't noticeable at first.

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    The ocean is a really big place. Why would you assume that the enemy can find your subs so easily?
    – Sneftel
    Aug 11, 2017 at 19:31
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    Russia and America spent lots of the Cold War following each other's subs around, with varying degrees of success.
    – pjc50
    Aug 11, 2017 at 20:39
  • There are listening systems that know the location of every sub. Not only do they know the position, but they also know individual subs from each other from their distinct sound. BUT, in this day and age you can find out where your cell phone is, it is not possible to not know your own nuclear submarine was destroyed! Royal Canadian Bandit, has made good points... it's mostly a matter of efficiency and cost, an ICBM sits on a Saturn rocket... people seem to underestimate the cost of firing something into space!
    – Quaternion
    Aug 11, 2017 at 21:35
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    @Quaternion "an ICBM sits on a Saturn rocket" No it doesn't: Saturn was specifically developed for space launches. Perhaps you're thinking of the Gemini programme, which used the Titan missile as the rocket. ICBMs since the 1960s have been solid-fueled; Saturn was liquid-fueled and that would be a huge disadvantage for an ICBM, since it's much harder to keep a liquid-fueled rocket ready to launch for extended periods. Aug 11, 2017 at 21:44
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    @DavidRicherby just read up, I stand informed. I didn't mean literally a Saturn rocket but most people know roughly what one is, I meant an expensive liquid fuelled rocket (for which the Saturn was an impressive example); which as you pointed out is never the less still wrong.
    – Quaternion
    Aug 11, 2017 at 22:15

This is what France and UK are doing at the moment, they both have only one active sub, but their doctrine is massive retaliation.

However the American doctrine during the most of the cold war was Flexible Response. Basically both sides agreed that in case of war they would not launch a massive strike on each other's cities. Nuclear weapons would have been use to target bridges, military installation and ... other countries.

Seven Days to the River Rhine, a WWIII scenario developed by the Warsaw Pact and declassified by the Polish government in 2005, showed that the USSR assumed NATO would target Polish cities in the Vistula river valley area in a first-strike scenario, as well as Czech cities, which would prevent Soviet reinforcements to east Germany. A Soviet nuclear counter-strike would be launched against West Germany, Belgium, the Netherlands and Denmark. Nuclear countries like UK and France would be spared.

In that kind of war a tactical nuclear weapon would be used with friendly forces in proximity and perhaps even on contested friendly territory. Submarines are not the best options here. Both the Soviet Union and the USA needed short range missiles or air force to deliver the nuclear strike.

Strategic bombers could deliver a tactical payload, also land bases are more accurate, communication is better, they can store more rockets, and the yield could be chosen. This all gives more flexibility in case of war. Subs are good when Mutual Assured Destruction is the desired output.

  • True, but I'm not sure it answers the question, as it only applies to tactical nuclear weapons. It doesn't explain why the USA and USSR/Russia have land-based missiles and aircraft to deliver strategic nuclear weapons. Aug 11, 2017 at 13:50
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    @Royal Canadian Bandit, the question is "why not ditch all that land and air based missiles and rely on submarines". Because most of that other weapons would be used during different kind of war.
    – user14816
    Aug 11, 2017 at 14:11
  • Not sure about the UK only having one active sub: en.wikipedia.org/wiki/… Aug 12, 2017 at 11:09
  • @ChrisNevill they have multiple subs in service, but I believe there is only necessary one at sea at any one time (the linked article suggests this has been the case rather than intent), which is what I think Tlen meant. Aug 13, 2017 at 13:15

It's worth noting that, at the very least, the UK does exactly this right now!

From your question:

So my question is, why not ditch all that land and air based missiles and rely on submarines.

This is the UK Trident Nuclear Programme:

Since tactical WE.177 free-fall bombs were decommissioned in 1998, Trident has been the only nuclear weapon system that is operated by the UK. Its stated purpose by the Ministry of Defence is to "deter the most extreme threats to our national security and way of life, which cannot be done by other means".

Now on to the "protocol" (again from your question):

Having satisfied themselves that the country is indeed gone, the protocol for them would be then to launch their missiles to the adversary that did it.

This is called the "Letters of last resort"

The letters of last resort are four identically-worded handwritten letters from the Prime Minister of the United Kingdom to the commanding officers of the four British ballistic missile submarines. They contain orders on what action to take in the event that an enemy nuclear strike has destroyed the British government and has killed or otherwise incapacitated both the Prime Minister and the "second person" (normally a high-ranking member of the Cabinet) whom the Prime Minister has designated to make a decision on how to act in the event of the Prime Minister's death. In the event that the orders were to be carried out, the action taken could be the last official act of Her Majesty's Government.

From a BBC documentary, the letters usually contain one of four options:

  • retaliate with nuclear weapons
  • not retaliate
  • (sub commander) use their own judgement
  • place the submarine under an allied country's command, if possible. The documentary mentions Australia and the United States.

I read a US general give this answer to the question back in Cold War days: "Suppose one of our missile subs disappears. Next week, another one disappears. What do we do?"

As Brythan said, "the real danger is an attack on the submarines. They operate remotely and spend long periods out of contact. So losses aren't noticeable at first."

It's impossible to destroy the land based missiles without their owner knowing it happened and who did it. It is conceivable that some technology breakthrough would enable the subs to be secretly destroyed, with plausible deniability at least.

This is all in Brythan's answer but I think it is the key and deserves more emphasis. Some other answers make similar points.

On another issue, I heard that US had a protocol similar to what was described for the UK that enabled sub commanders decide if the US had been destroyed and fire their missiles without a direct order. I heard it from someone who knew a lot of classified information--for what it's worth.


Well, for the Russian's they have Dead Hand.

Which is to suppose to help prevent a hasty decision in fear of leadership being wiped out by a surprise attack. I am not aware of any allied nations with the same type of 2nd strike 'rule' and I don't know if subs have the individual authority to perform a 2nd strike. Although I have heard that in the case of U.K Subs they were to assume all was lost if no BBC broadcast was available.


One other problem with submarines, in the event of the doomsday scenario where the nation's leadership is taken out is - who do you retaliate against? Submarines have very limited ability to communicate while submerged, just the very slow ELF communications, which means they have limited access to information on events within the flight time of an ICBM - twenty to thirty minutes prior to the detonation.

Today, there are two major nations who could launch such an attack: Russia and China, plus at four others who have the capability: the UK, France, India and Pakistan. N Korea is working on ICBM capability, although the current fears are more media hype than reality. Israel has nukes, but no ICBM's - theirs appear to be built for aircraft or drone delivery.

Even ruling out Israel, the UK, and France, and ranking India as highly unlikely, and Pakistan as unlikely unless a radical group got control of one of the missiles and that Pakistan has developed missiles with true intercontinental range (they don't appear to have done so), that still leaves two major targets. Which one was it?

So, you're a sub commander, and your nation got hit. Who did it? You should probably have some idea of who might have done it with events leading up to such an attack, but do you unleash your devastating arsenal without knowing for sure?

Or was it a submarine launched attack, in which case you'll have trouble figuring out which nation is responsible?

Was this was a rogue attack, launched individually by radicals who took control of a nuclear submarine, and not an act of state policy? That may have happened - the Soviet submarine K129 that sank in the Pacific in 1968 appears to have been sunk by the self destruct of one of it's nuclear warheads that ignited the missile fuel and burned a huge hole in the bottom of the submarine - which would only happen if there was an unauthorized attempt to arm and launch the missiles. Read Dr John Craven's book The Silent War, where he details what was concluded about the K129, and why the CIA spent a fortune to salvage the wreck in the 1970's. It wasn't to recover code books or missiles.

Or did terrorists smuggle a purloined nuke into your capital and take it out, in which case you won't have a target.

Surface based nuclear arsenals will have much more rapid communications available, and can react more quickly, with better information. They will have access to tracking information to identify the source of incoming missiles, that submarines won't have, and may not be able to get if the nation's communications systems have been damaged as well.


Thinking about the UK:

Option one, the submarine is told to fire while the UK still has a someone in charge, this is no better than having to launch a land based missile, as taking out all commanders and coms systems is not much harder than taking out all ground based missiles.

Option two, the submarine can decide itself to fire, and you have to trust the people on it to do the right thing.

The UK has “option two” and our submarines can fire without needing to be given a code to enable the nukes. The USA doesn't trust their people as much, so their nukes all need a code that only the president has access to before firing. But what if the president is taken out……

Submarine don’t gain you much unless you trust and enable the captain to fire the missile when he cannot “phone home”.

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    And my sympathies to the commander of that missile submarine. May they never find themselves in the position where they must evaluate killing millions of people with nothing to work with but the information they have in front of them. I do not envy that job.
    – Cort Ammon
    Aug 11, 2017 at 16:39
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    @CortAmmon They do have a secret letter from the prime mister saying what to do. MAD only depends on the other side knowing they can't stop a response, not on them knowing how likely a response is. Hence the letter is destroyed unread on an exchange of prime misters and is one of the few documents that are still hand written so there are no copies on computer etc. Aug 11, 2017 at 16:43
  • I have knowledge I probably shouldn't have. The command to launch nukes sent to US subs is not actually required to arm the nukes. They can be armed using information only present on the submarine. The CO and XO are trusted not to order such a thing, and their cooperation is required in any reasonable scenario.
    – Joshua
    Aug 11, 2017 at 19:57
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    "But what if the president is taken out" is why "their nukes all need a code that only the president has access to before firing" is not actually correct. The President's code is used just to authenticate that it really is the President giving the order, not to actually arm the missiles. Even if they did make the decision to launch, that particular code would never go to the actual missile launch locations. The Vice President also has a similar code in case the President is gone, but neither code is actually needed to arm or launch of the missiles.
    – reirab
    Aug 11, 2017 at 23:24

Submarines are:

1) Expensive - A comical definition of a boat is a hole in the water that you have to pout money into to keep from sinking. Submarines doubly so, because they are designed to sink. For every boomer you can put to sea, you could probably dig 10 ICBM silos.

2) fragile - An ICBM silo can be hardened and fortified against enemy nukes, and guarded by trigger happy teenagers with machine guns, defended by radar, fighters and surface to air missiles. Subs can be sunk with a torpedo from a wooden PT boat or a underwater mine. If you invest billions into your MAD defensive measures, it kinda sucks when they can be taken out of play for a few thousand bucks. Attack subs are designed to find and sink enemy ships, this includes your boomers. And based on point 3 (below) how can you ever even tell if you enemy has found and sunk all your boomers? You have no way of knowing if they are just fine sneaking around enemy harbors getting ready to attack or if they are all sunk.

3) Hard to talk to - If you want your boomers to be stealthy and sneaky, you can't have them sending or receiving a lot of info. Communication is much more limited than with a static launch site.

4) limited range/payload - Boomers are really bug subs, but even they have range and payload limitations. MAD strategy suggests that you want to target a large number of population centers with big payloads to kill as many as possible. Boomers can carry some large yield weapons, but probably not as many or as big as you would like to assure a successful MAD strategy.

also, boomers aren't really hide and retaliate weapons. They are mobile and sneaky, which makes them better as offensive weapons. I think the idea was that if you launch a nuclear cruise missile from off the coast of your target, you only give them a minute or two to react. An ICBM might be able to hit a target on the other side of the globe, but they have a ten to thirty minute flight time, giving a wary opponent plenty of time to launch a return volley. I believe that Boomers were initially developed by the US and soviet union as a first strike weapon.

I think moving all your nuclear forces to boomers is actually more destabilizing and scary, as it isn't a sign that you are insuring a MAD strategy, but that you intend to attempt an aggressive first strike. If saw an enemy do this, I would feel I HAD to make my own first strike before they could get their boomers into position.

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    The current US/UK SLBM is Trident II, which has a 12,000km+ range, comparable to the US's silo-launched Minuteman III. To all intents and purposes, it's an ICBM. I would suggest that you replace all the "I think"s, "I feel"s and "I believe"s in your post with actual researched information. Aug 12, 2017 at 8:39
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    Note also that silos aren't appropriate for a smaller country such as the UK. England has 55 million people in an area that would make it the 32nd-largest US state: I doubt there's anywhere in England that's more than 30 miles from a city of 50,000+ people so any silo would be inviting the enemy to send nukes to somewhere very close to a lot of people. So any British silos would probably have to be in mountainous areas of Scotland, which has its own difficulties. Aug 12, 2017 at 8:46
  • Sure they are. An enemy willing to employ nuclear weapons to take out UKs missile silos aren't going to care about killing civilians. They are using WMDs, casualties are the goal. Moreover putting them in proximity to population centers is actually a plus, because such an attack would provoke world outrage at the mass casualties and insure a swift and truly violent response from allies. But it is moot, I am not arguing FOR silos, I am just explaining why the idea of using boomers for defense is a little impracticable.
    – Roger Hill
    Aug 14, 2017 at 17:07
  • One argument is that attacking silos near population centres would provoke world outrage at the civilian deaths. The counter argument is that placing silos near population centres would provoke world outrage at the use of human shields. At least, that's what we call it when governments we don't like do that kind of thing. Aug 14, 2017 at 17:32

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