Why is the Nuclear Triad needed if nuclear subs can’t be realistically countered?
In: Technology
Nuclear subs have low capacity, you can’t rely on them alone to completely obliterate a nuclear superpower’s military capabilities.
They’re mostly there for the “second strike” capability they offer.
While pop media always focuses heavily on the MAD/nuclear winter scenario where a nuclear exchange occurs and then society immediately ends forever, the nuclear powers don’t truly plan/expect this to happen.
Modern cities are glass and steel and concrete, they’re not going to burn like Hiroshima did and won’t generate the kind of ash clouds required to blot out the sun and collapse the global ecosystem. Military plans for world war 3 fully expected the war to have a day 2 and a week 2 and a year 2 involving more conventional weapons and tactical nuclear exchanges.
The nuclear subs are here for that – when all your launch sites and airfields have been nuked and your conventional nuclear capabilities are now heavily degraded.
Well the answer is probably more political than military. It started with the US Air Force, then they put missiles on the ground (so the Army got their stuff) and the Navy wanted their own stuff. And therefore it became doctrine.
It definitely makes some sense. Bombers take a fairly long time to travel so aren’t the best “quick response” arsenal and this reduces their deterrence effect. Ground based launchers can’t move around and are probably the first targeted areas. Submarine launched ballistic missiles came about effectively around the late 1960s. Having all three options makes nuclear defense much more expensive for the USSR.
1) Whoops, we didn’t realize that the enemy’s sonar capabilities actually let them know where our subs were 100% of the time and they just sunk all of them before launching their own strike. This was a realization that the Soviet Union actually had in the 1980s and led to their shifting resources away from ballistic missile submarines and towards surface ships like the Kirov and Kuznetsov classes.
2) Whoops, our enemy launched a massive nuclear strike on us and, with knowledge that our own submarine launched missiles could only hit their major cities from a few points off their coast, positioned their entire navy there and then sunk our submarines when they surfaced to fire (or maybe they were just able to outright determine planned launch sites through some form of espionage).
3) It turns out that launching a ballistic missile from a submarine is an order of magnitude more expensive than launching it from a silo, and a further order of magnitude more expensive than dropping a bomb from a bomber. By only building ballistic missile submarines, we ended up with a tiny fraction of the retaliatory ability than we would have had with a diversified arsenal. So – Whoops, it turns out we didn’t have enough missiles to launch a credible retaliation and our enemy decided that the maximum possible damage that our submarine forces could inflict was, to them, an acceptable loss to wipe us out.
The point of the nuclear triad is that its a cost effective way to guarantee that there is no single defense that your enemy has, but which you aren’t aware exists, that prevents you from launching a credible counter-strike.
Because most nations can’t truly effectively field nuclear subs in sufficient numbers.
Even the USA, who spends way more on military than any other nation, only has a few “boomers” and they are constantly having a large portion of them in dock getting maintenance and repairs/upgrades. The new Columbia-class boomer subs are already seeing serious delays in construction and commissioning. And this is fucking America… now imagine the rest of the nuclear powers who have way fewer resources and smaller military industrial complex.
If nuclear powers could field a fleet of 40 nuclear-armed subs (assuming only about 10-15 of those actually in use actively at any point, and the majority in home port for refit and maintenance) then maybe they’d give up on other capabilities… but even then, all your adversaries would just focus on tech to try to focus on subs. Having 3 different strategies that are all field-able makes it exponentially harder for enemies to cover all types, with subs just being the most potent for a quick strike or quick retaliation
The entire idea of mutually assured destruction relies on our enemies actually wanting to survive. If they absolutely know that a nuclear attack on the United States ends their lives also, the thinking is they would not attack us. This probably holds for Russia and China. Less so for “rogue” nations like North Korea.
But imagine an enemy that discovered a secret way to render our subs useless. Something we had no idea they could do. That might embolden them to try a “first strike”. No subs, no retaliation, they win.
The idea of the Nuclear Triad, is that we hope no nation could possibly undermine all three methods of retaliation (subs, missiles, bombers); meaning no sane nation would even try.
**tl;dr We don’t want a nation that develops ground-breaking new anti-sub technology to think they could win, so we have alternate methods of retaliation as part of mutually assured destruction.**
I’m reading Arsenals of Folly by Richard Rhodes, who also wrote Making of the Atomic Bomb. A major theme of this book is that the nuclear arms race is not necessarily rational and a lot of public-facing justification shouldn’t be taken at face value.
Nuclear weapons were initially only able to be used by the Air Force. The Air Force “owned” nuclear weapons until smaller warheads became available and the navy and army started adopting them. Inter-service rivalry was strong in the Cold War, and the idea of a triad was largely a navy justification for their mission and budget.
There isn’t anything innately magical or logical about three delivery mechanisms. Indeed, battleships and infantry-carried “mines” could be used to deliver sizable nukes, so “triad” was an oversimplification anyways. One, two, or a hundred independent ways to nuke someone might be sensible, depending on what you’re trying to do.
Subs are hard to detect compared to ICBMs and hard to destroy compared to bombers. Initially their missiles weren’t accurate enough to reliably destroy armored missile silos, so they were envisioned as a “second-strike” weapon, to be used against cities if your enemy shot their missiles at you. This is a fairly clever role, as the mass slaughter of civilians goes, because if the subs are undetected then starting a nuclear war *is* suicide. Subs are an excellent guaranteed of MAD.
Things are unfortunately changing. New guidance and fusing is challenging the idea that sub-launched missiles can’t be used preemptively against missile silos. With relatively shorter ranges and correspondingly shorter warning times, subs may become a credible “first strike” weapon, potentially able to destroy enemy nukes if fired without warning in a surprise attack. Taking that to its logical conclusion, ICBMs become potentially irrelevant and MAD weakened, and the prospect of preemptive nuclear war may become tempting.
Air defense is much more sophisticated than it has been in the past, so bombers are a suspect leg of the triad. Today, a survey of nuclear arms might show ICBMs, mobile-launched missiles, sub-launched missiles, and bomber-launched cruise missiles as a more up-to-date nuclear arsenal, with ICBMs being potentially the most vulnerable leg.
It’s not. The primary reason for the Triad is that each of the US’ Armed Forces wanted their own nuclear capability.
That said, nuclear subs do have weaknesses. Their missiles are smaller, which means they have a smaller payload and a shorter range, which means they need to be fired from close to the target. Somewhat paradoxically, immediately after launch is the easiest time to intercept ballistic missiles, when it’s still accelerating and before it’s separated into a dozen warheads that need to be independently destroyed.
And the three parts of the Triad do serve different functions. Nuclear SLBNs are undetectable prior to launch, Nuclear ICBMs are designed to be impervious to a first strike, and Nuclear Stealth Bombers are able to penetrate an enemy’s air defense system much easier than ballistic missiles can. We’ve never had a nuclear war, so we don’t actually know which method works best, so the US maintains all three to be on the safe side. Especially because who knows when someone invents a type of sensor that allows submarines to be found easily. Kinda basic don’t put all your eggs in one basket deal
Submarines with nuclear missiles can be countered. Due to their small size the submarines can not carry many missiles and the missiles are smaller so have shorter range. Firstly this means that the submarine have to be rather close to its target. Places like Moscow and Chicago is therefore out of range of most realistic submarine attacks. The submarines generally stay in open water and may have to move inn closer to shore in order to reach the targets they want to. That makes them vulnerable to attack submarines and aircraft. Just the act of being hunted prevents the nuclear submarines from going close to the surface and slowing down in order to launch the missiles.
Even if the submarines gets within firing range of their targets and if they can get into position to fire their missiles the missiles have to cross land at a low altitude to get to their target. So they can be shot down by surface to air missiles and other anti aircraft weapons. You would normally fire lots of extra missiles so not all of them can be shot down but again submarines have limited space and therefore limited missiles. It does not help to have 25 missile tubes when you regularly hear about drone and cruise missile swarms in the hundreds of weapons fired at once all get shot down both in Ukraine and in Israel. A single submarine can not penetrate those defenses. Even all the submarines in the fleet would have a hard time getting even a single warhead through.
There’s been some discussion, at least in the US, that it’s not strictly needed for deterrence, and that deterrent requirements can be met solely with submarines. The UK, for example, has submarines as the only component of its nuclear deterrent.
That said, the different legs of the triad each have their own benefits and help reinforce each other.
– Land-based silos are very quick to react, and are able to launch missiles within minutes. Subs take longer.
They also act as “missile sponges”, in that an enemy seeking to minimize the possibility of retaliation is going to try to neutralize the land-based silos first, which can use up a substantial number of the adversary’s warheads, leaving fewer for other still-strategic but less immediately-threatening targets like military bases and political leadership. Since silos are hardened and missiles are not perfectly accurate, an adversary would want to target each land-based silo with multiple warheads of their own to ensure their destruction. Nuclear warheads and missiles aren’t free, so an attacker would need many more warheads than the defender has silos, which increases the costs to the attacker. When both are party to arms control treaties that limit the number of deployed warheads, this puts strong pressure on the would-be attacker’s targeting decisions (“Do I try to neutralize their silos in a quick sneak attack and not have any missiles left for other targets, or do I risk counterattack by not striking the silos and instead attack other targets?”).
Most silos are in remote, sparsely-populated regions so immediate casualties would be low, thus giving the defender the advantage. Once a silo launches, it poses no further threat and there’s no value in targeting it (unlike a sub, which may launch only some missiles, have more in reserves, and would need to flee the launch area since it’s now clearly announced its location). They’re also relatively cheap, as a silo is just a fancy hole in the ground, maintenance is relatively cheap compared to subs, and you generally need less people-per-missile to support the mission. Since they’re located one one’s home country, they’re easy to protect and hard for an adversary to attack.
There’s also other types of land-based missiles, like road- and rail-mobile launchers that can be kept around a base during peacetime for ease of security and maintenance, but deployed to various dispersed positions during times of elevated tensions. These have various advantages and disadvantages compared to fixed silos.
– Air-launched systems (bombs and cruise missiles) are more flexible, since you can maneuver the launching vehicle into a more favorable position prior to launch. Cruise missiles can take long, meandering paths to avoid detection and interception. Aircraft can be moved around and publicly displayed as a show of military force and political power. (See the various posturing with nuclear-capable aircraft by Russians around Alaska, the US around North Korea, etc.) Basing nuclear weapons in allied countries (under the control of the nuclear state) can provide political reassurance to allies about the nuclear state’s commitment to mutual defense.
– Subs are hard to detect and highly mobile. They all but guarantee a viable second-strike capability and thus deter an adversary from thinking they can win by performing a sneak attack. However, their very invisibility makes them difficult to posture with (though there have been examples of US Ohio-class subs making highly visible port calls in allied countries). Maintenance and crew costs are much higher.
Because the whole idea is based on overkill. For simplicity sake assume there is a 5% chance someone will find a way to make one of the legs obsolete overnight. Also assume that method doesn’t work for the others. Then there is only a 0.0125% chance that all three will be obsoleted together. There is however a nontrivial 14.3% that at least one of them will.
This is not obviously an oversimplified version but it boils down to not having to have a perfect system and three independent ones like this give you an outsized chance of been able to respond in a way that making the first move is a losing proposition even if you come up with some magic way to invalidate one of them.
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