Preventing or Containing Tactical Nuclear War at Sea
By: Joe Buff
Tags: Cold War, Nuclear Weapons, National Defence, Submarine, Foreign Policy

An early Cold War underwater US nuclear test blast devastated a fleet of target ships. (Photo: Wikipedia)

By JOE BUFF, MS, FSA, President of Joe Buff Inc, “An Independent Defense Think Tank of One,” est. 1997.

This topic is especially pressing now, as the US Navy is (1) looking to once again deploy some low-yield tactical nuclear warheads at sea on the weaponry of surface ships, as a further nuclear deterrent, as it did back during the First Cold War, and is also (2) planning for the first time to render more flexible the nuclear-deterrent capabilities of America’s submarine-launched ballistic missiles (SLBMs) by deploying some low-yield tactical warheads on our now-high-yield-only, thermonuclear-armed strategic deterrent nuclear submarines (SSBNs).

It should be emphasized that these measures, if given final approval by Congress and then implemented by the Pentagon, would serve merely to reimpose parity against the nuclear-armed naval forces of Russia and China, which have either long deployed their own tactical nukes at sea, or are not constrained by any signed treaties or declared postures from doing so.

As such, this American up-arming move would not (as some nay-sayers argue) “trigger an arms race.” Rather, it would restore a measure of American deterrence, stability, and security on the high seas, in international waters, where both China and Russia persist in aggressive territorial expansionism and rising military intimidation. By enabling, if ever necessary, U.S. Navy prompt response and in-kind retaliation near the origination point, at sea, this move would allow containment of any enemy “tactical-nuclear Pearl Harbor out in blue water” — without needing either horizontal (onto land) or vertical (higher yield) escalation of the counter-strike(s) made by American forces.

Current world conditions in this new era of renewed Great Power Competition (“Cold War Two”) — an era it is important politically and psychologically to emphasize was initiated by America’s adversaries, not by us — do add urgency to the topics of best avoiding limited tactical nuclear war at sea, and best posturing strategic anti-submarine warfare in order to keep the global nuclear (and also the big conventional) peace. The very same basic measures for such oceanic peacekeeping could apply as are available on land: arms-control treaties, and capable deterrence Triads.

The harsh fact is that nuclear weapons do exist in the hands of a number of states (currently nine, maybe going on ten), which are arrayed in various, persistently-adversarial relationships with one another. Another hard fact is that nuclear disarmament movements have been active since the dawn of the Atomic Age in 1945, yet so far they have not succeeded in preventing the gradual spread to an increasing number of countries of an increasing number of nuclear warheads delivered by an increasing diversity of weapons platforms. (The nuclear arms reductions by the US and USSR/Russia around the end of the Cold War were really just pragmatic, politically expedient eliminations of unnecessary and very expensive overkill inventories within their permanent deterrent arsenals, and cannot in all fairness be characterized now as ever intended by national leaders to be continued onward all the way down to Global Zero.) On the other hand, over that same extended historical period of 75 years and counting, mutual nuclear deterrence post-Hiroshima/Nagasaki has succeeded in preventing any nuclear attacks, or even any big inter-superpower conventional wars.

Given these wider logical “axioms” characterizing today’s world, what if anything can be done to control the types of weapons available for starting and fighting a limited tactical nuclear war at sea? Recall that an early Cold War study by France suggested that this type of war, fought out in blue water far away from civilian populations, if it actually did stay limited could be survivable, and perhaps even winnable by one side. This makes such a warfighting scenario particularly (uniquely?) dangerous, even as a mere possibility someday. Heightening the dangers even more is that, as some Western defense experts believe, Russia under Vladimir Putin has adopted a policy of “escalating to de-escalate,” whereby Moscow might make tactical-nuclear first strikes in time of armed conflict with NATO or with other adversaries (perhaps in the volatile Middle East, given Moscow’s ongoing/expanding military entanglements there?). Could a global ban on anti-submarine warfare (ASW) use of tactical-nuclear (fission) depth charges and torpedoes be of help to quash this extremely dangerous Russian policy, at least in the oceanic realm? Such a ban would restore a wide escalation “firewall” of sorts between conventional arms and strategic (high yield) nuclear arms usage, in the key potential warfighting domain of the watery international commons.

Can Russia be persuaded, by a combination of inducements and punishments, to relinquish any deploying of its Poseidon long-range strategic-nuclear drone submarine/torpedo hybrid, which is intended to obliterate adversary (e.g., American and other NATO) ports, harbors, and other coastal installations — which are also major population centers? Given the long-term trend by NATO states to generally more precise (accurate) and discriminating (lower yielding but still effective) nuclear weapons deployed in NWS arsenals (to avoid nuclear winter after-effects), along with a relinquishing of any intentional nuclear attacks directly on civilians (for moral/ethical and humanitarian reasons), is Russia just looking to spread raw fear via such tactics and deployments — which are tantamount in today’s world to the practice of nuclear terrorism?

From a purely military perspective, ignoring the awful wider implications concerning (1) nuclear-fallout pollution spreading to land, and (2) likely escalation to Armageddon, one has to admit that tactical nukes used at sea have undisputed technical advantages: They have a huge radius of destructive effect, which makes them much more effective than high-explosive munitions against enemy pinpoint (ship) and/or area (fleet) targets, thus obviating the need for either a very refined fire-control solution or a very capable homing system — such as modern naval warfare does demand of h.-e. warheads. In addition, the lack of vast amounts of combustible materials during a naval war on the high seas, compared to the forests and fields, factories and cities of any occupied land mass, mean that tactical nuclear war confined to blue water might not produce a deadly Nuclear Winter aftermath — although it could produce a Nuclear Summer, in which wholesale destruction of the ozone layer leads to killing doses of hard ultraviolet exposures from the Sun.

A 12-kiloton Hiroshima-sized depth charge would have an effective mission-kill radius against a modern nuclear or diesel/air-independent-propulsion submarine of about two nautical miles — much bigger than any high-explosive depth charge. Such a warhead fitted to a torpedo would have a similarly large mission-kill radius, again much greater than that of any conventional fish. The nuke fish would be very difficult to spoof, decoy, or evade — especially if it simply moved dumbly, in a straight line with a timer to set its range for detonation. In particular, the vast mission-kill radius of an underwater strategic-nuclear blast, of say 1 megaton yield, could with a single weapon eliminate an entire escorted merchant-ship convoy, or an entire aircraft-carrier or amphibious-warfare strike group.

The relative ease of any (even rudimentary) adversary nuclear weapons-owning state — perhaps a North Korea or an Iran — acquiring the additional, nuclear-capable, depth-charge or torpedo hardware needed to manufacture tactical-nuclear (A-bomb, i.e., fission) ASW warheads, and the tremendous advantages these would have over conventional high-explosive ASW weaponry, could present a belligerent-enough nuclear-armed aggressor with an awful temptation: the temptation to resolve frustrations over being outfoxed by U.S./NATO submarine forces’ superior stealth and smarter tactics and ship-handling, by actually nuking one or more possible submarine contacts (POSSUBs) during a bad-enough international crisis. The adversary might hope that such use of low-yield fission bombs, deep underwater, might go undetected by the rest of the world, or, at least, might be perceived as signaling an intention to limit a tactical nuclear conflict to the oceans only. But obviously, this first-use scenario would utterly destroy any prevalent No First Use norms, and would thus be dangerously destabilizing on a global basis.

What can be done about this? Right now nothing in international competition is certain, and dogmatism of any ilk could lead to disaster, so perhaps it is best to simply mention the cautionary issues that any responsible national government needs to be aware of. Would negotiating a ban on tactical nuclear ASW warheads be impossible to achieve, and impossible to enforce against cheating? Modern versions of the Cold War-era’s long-distance surveillance sonars, SOSUS, as well as more local submarine and surface-ship sonar arrays, would probably quickly detect any undersea adversary nuke first use — but that would only be after the fact. Is the only practicable way to prevent tactical nuclear war at sea not to try to ban all fission weapons there, as some sort of technical firewall against escalation from conventional ordnance, but instead to be prepared with a strong nuclear deterrent by being able to retaliate promptly in kind against any adversary’s nuke first use? Has the ever-present post-First Cold War danger, that America and our Allies would at some point in the future be forced by adversary misbehavior to return to a posture where tactical nuclear weapons are deployed on our navies’ ships and subs for effective deterrence, actually come to pass as we enter the year 2020? It is precisely this question which is now under pressing study and vehement debate by the White House, the Pentagon, and the U.S. Congress. The future of worldwide nuclear peace, and with it the fate of humanity, may very well depend on coming up with the right, genuinely effective set of updated National Nuclear Strategy and Posture parameters.

It was established practice during the First Cold War — a norm? — for nuclear submarines to, in some circumstances, carry high-yield, thermonuclear-tipped torpedoes for in-theater, operational/tactical offense and defense. Since the strategic-deterrent nuclear submarines (SSBNs) of both sides were already carrying a large number of such hydrogen bombs on their SLBMs, this made sense, in the specialized context of strategic sub-on-sub deterrence and strategic ASW operations. (That is, undersea warfighting and ASW in which the military platforms involved were armed with H-bomb ballistic-missile warheads intended for use against each other’s distant strategic targets on land.) But does this old “norm” make any sense at all in the 21st century, in which the old US/USSR bi-polar matchup has been replaced by a much more dangerous, unpredictable, and increasingly proliferation-prone multi-polar competitive arena? That arena already sees a significant growth in the number of military submarines among nations that might sooner or later deploy nukes on them — such as Pakistan, India, North Korea, and even Iran.

Arguing to the contrary, at least as a Devil’s advocate for a moment, would the U.S. instead gain persuasive powers in global nuclear arms control and counter-proliferation efforts, by pointedly avoiding use of nuclear torpedoes, depth charges, and tactical cruise missiles, in a continuation of our immediate-post-Cold-War posture? No. It is my considered professional opinion that “the U.S. leading global nuclear disarmament via our unilateral fine example” has already been proven by much sad recent real-world history to not be the way to go.

Or, arguing for a pragmatic middle ground that relies on current U.S. Navy conventional torpedo technological superiority, are the latest versions of modern American super-smart heavyweight Mark 48 torpedoes with conventional warheads adequate to protect America and our vital interests against all comers, no matter how heavily those adversaries are armed? As stated above, since the end of the Cold War the U.S. Navy has not actually deployed any strategic or tactical nuclear warheads on its submarines and ships except for the high-yield, strategic SLBMs on its SSBNs. In contrast, a Russian admiral has stated publicly that Russian fast-attack submarines (SSNs) do carry low-yielding nuclear torpedoes. So we see, once again, that it is America’s adversaries and not our own government that have “escalated” and “proliferated” the extent of their deployed nuclear armaments — necessitating American reciprocity as an inherently defensive move, to restore deterrence, assure mutual stability, and insure nuclear peace.

For completeness, we should briefly consider another aspect of modern undersea warfare and ASW operations: While Russian-style conventionally-armed Shkval rocket torpedoes, capable of speeds up to an amazing, intimidating 300 knots underwater, might be seen as the “poor man’s nuclear torpedo,” the U.S. Submarine Force prefers not to deploy such weapons, for very good reasons: The extreme noise of their rocket engines immediately betrays the location of the sub that fires one, while also disrupting that firing sub’s tactical sonars at the crucial moment of engagement and counter-engagement. The super-cavitating fish’s white-hot rocket exhaust precludes deploying thin guidance wires, making post-launch targeting refinements from the launching submarine’s skilled crew and exquisite sensors quite impossible. Although rocket torpedoes do travel in a straight line very quickly indeed, they are very difficult to engineer-in the capabilities needed to accurately track and nimbly maneuver in pursuit of a stealthy moving target. Submarines can maneuver in three dimensions, evading a rocket torpedo — but not a super-smart, actively homing and wire-guided, conventional Mark 48.

We end this discussion by noting that arguments can be made both for and against consistency in what the U.S. Navy does with tactical (and strategic) nuclear weapons going forward, as to what components of the Fleet (types of ships) get them, and what types of deterrent targets (surface ship, submarine, airborne, and/or landlocked) they are potentially used against. The ultimate decision by the U.S. Government’s policy-setting deliberative organs will undoubtedly include some argumentation that is stridently political, and/or starkly emotional-psychological, and/or Hobson’s-choice fiscal/budgetary, and not just purely professional-deterrence needs/effects driven. But the national-defense related, military science- and strategy-based lines of objective reasoning should be allowed and required to predominate.

The options exist to re-introduce tactical nuclear warheads to (1) surface ships only, for use against other surface ships and land targets only, or (2) to also deploy them for ASW by surface ships, or (3) to deploy them as well on submarines’ torpedoes and cruise missiles for use against other subs as well as surface or land targets. Other, finer distinctions in the extend of deployment and use are obviously also possible. Practical decisions will surely be based in part on costs, since the more different makes and models of different individual weapon types are to be equipped with nuclear-armed warheads, the greater will be development, procurement, logistics, maintenance, and training expenses.

I would argue that, here, consistency is much more than merely “the last refuge of weak minds,” (to quote a well-known aphorism). Realistically, since the whole point of increased nuclear weapon deployments, if any, by the U.S. Navy is for effective mutual nuclear deterrence at sea (and beyond) of adversaries, any move to place nuclear warheads on our surface warships ought to be mirrored by a similar move on our undersea warships, and if such warheads are placed on our missiles, then they should also be placed on our torpedoes, depth charges, and also the hybrid ASROC-type ASW rocket-torpedoes. Lastly, I would emphasize that the Pentagon absolutely should continue its policy of “human in the loop” in all nuclear-weapons handling and potential employment. Drone (unmanned) ship/sub hardware, and robotic/artificial-intelligence warfighting (AI) algorithms, are most definitely not the environments to house any American nuclear-weapon decisions and actions!

(Article Image Credit: Health Magazine)