This week, Russian President Vladimir Putin has been meeting with his top military folks in Sochi to talk about planning and modernization across the entire Russian military. Unsurprisingly, the confab tackled nuclear weapons and the US's plans for ballistic missile defense. And anytime the Russians start talking about getting new and better nukes, folks in the West (also unsurprisingly) get a bit agitated.

The big bombshell, however, was a lingering shot of a page in the Russian general's briefing book, which described a long-range, underwater drone, armed with a high-yield "salted" nuclear warhead, which is designed with a casing intended to maximize the production of highly radioactive fallout.

There's some speculation that this happened accidentally-on-purpose, to rile up the West. There's no way to know for sure, but the surprise reveal does suggest that some spookier things may be afoot.

But let's start with what this is — or isn't. It is a concept, not deployed equipment. It's not a torpedo, at least not in the typical sense. Torpedoes with nuclear warheads have been a thing for a while (and turn out to be a great way to mess up a carrier battle group), but the device described in the presentation isn't intended to go after ships — it's intended to go after ports and coastal cities.

Some are connecting this system with the one that Bill Gertz wrote about in September, a secret Russian nuclear-armed drone called Kanyon, which would have warhead yields in the tens of megatons.

If these are referring to the same program, then it's not a dirty bomb, despite some claims. The warhead is certainly dirty, but it's what nuke guys call a "salted" bomb. A dirty bomb (more formally known as a radiological weapon) is just radioactive stuff spewed all over with the aid of a regular explosive warhead. A salted weapon is a regular old nuclear warhead designed to produce maximum fallout. They differ in that the dirty bomb doesn't involve a nuclear explosion. According to reports, the warhead on this new weapon would, and it would be a big-ass nuclear explosion, which would, in turn, generate a humongous amount of radioactive fallout.

A salted weapon in the tens of megatons is more than a bit odd. By most prevailing custom, anytime someone lights off a nuke that large on the downtown waterfront, one can assume that the surrounding city has been pretty much destroyed. Creating an enormous, high intensity plume of fallout to go with that is tad bit more than is strictly necessary to ruin someone's day.

One translation of the page suggests that the device would be capable of travelling roughly 6,000 miles at a depth of 3,000 feet and a speed of up to 60 mph. Those are speeds, distances, and travel times that most certainly add up to a nuclear-powered strategic weapon, not merely a ship-sinking torpedo.

Is this a big deal? No and yes. Right now, it's just vaporware and speculation, so there's no reason to start digging a fallout shelter. And even if it were a real thing, it's a pretty special-purpose weapon. Certainly not a dramatic game-changer. However, if you look closely, it suggests that one of the fundamental strategic truths of the 20th century about nuclear weapons may be coming to an end.

Most folks have heard of mutually assured destruction in relation to nukes. It's the idea that if you launch your nukes to devastate me, I can still fire off enough nukes to annihilate you before I die. Thus, any large-scale nuclear war is unwinnable, because in the end, everyone dies. And "everyone dies" is not considered a victory condition, except to the most dyspeptic of people.

All the old-school thinking about mutually assured destruction and deterrence relied on the basic rules of intercontinental ballistic missiles (ICBMs). First, particularly with the advent of good early warning satellites, there's no way to really disguise the fact that you've just launched a couple thousand missiles at someone. So before your nukes have a chance to land, the other guy knows where his revenge should be aimed and has time to launch a retaliatory strike before disappearing in a nuclear fireball. A second feature of ICBMs is that shooting them down or stopping them is enormously hard, even today.

The basic rules of technology and physics have generally meant that you could always count on getting a devastating retaliatory blow in — what nuclear deterrence folks call a "secure second strike." Therefore, anything that gives someone a reason to believe they don't have to fear a nuclear counterattack weakens deterrence and makes nuclear war incrementally more likely.

Now, the first and easiest way that deterrence can unravel is if the would-be attacker is just flat-out crazier than a briefcase full of shaved, glue-huffing ferrets. Both the US and Russia suffered devastating surprise attacks in World War II — the US with Pearl Harbor, and the Soviets with Hitler's invasion of Russia in Operation Barbarossa. The lessons of those attacks are so deeply embedded in the respective strategic cultures that planners will likely always feel obligated to include a "massive surprise attack" contingency in their doomsday planning.

Watch VICE News' Troops and Tanks in Moscow: Russia's Victory Day

This quirk of history means that mutually assured destruction never became an absolutely indisputable article of faith for nuclear war planners in either country. Neither side has been able to truly and completely convince themselves that there is absolutely zero danger of a massive "bolt from the blue" nuclear sneak attack from someone, somewhere, someday.

Mercifully, throughout most of the 1990s, Russia and the US were both pretty far from that headspace. Then 9/11 rolled around and spooked the US something awful.

Among other things, it had the effect of eroding US faith in deterrence. The US's reasoning goes that it should have been quite obvious that taking down the Twin Towers and hitting the Pentagon would get the US riled right the hell up, which would immediately be followed by a lavish application of beatdown. The fact that the threat of excessive use of military force wasn't sufficient to dissuade someone from taking a shot at the US was deeply disturbing to US strategic culture.

This erosion of faith in deterrence was part of the rationale behind the Iraq War (expressed in the many talks about preemptively invading Iraq before Saddam enabled an attack on the US using weapons of mass destruction).

Today, this lack of faith in deterrence manifests itself in the newest lease on life for the US's ballistic missile defense program (BMD, a.k.a. "Star Wars"). If the US cannot be fundamentally, 100 percent convinced that North Korea, Iran, or someone else won't get a bright idea about nuking New York, Washington, or Portland, then the US will want to have a backup plan.

But herein lies the rub. Unfortunately, BMD leads us right into a second threat to an assured second strike: anything that allows one side to block the other guy's attack. If one side can get off a clever enough first strike that the opponent might only be able to get off a couple dozen missiles, the prospect of a couple dozen nuclear fireballs exploding over the attacker's cities is still enough of a threat to prevent any sneak attacks. However, any BMD, no matter how inefficient, that can defeat even a few dozen missiles can leave one side with the sneaking suspicion that they've become vulnerable to a massive nuclear attack. And once people start harboring those fears, they tend to get a bit agitated.

This explains one of the other developments in Putin's big Sochi military retreat: his promise that Russia will develop measures that will allow nuclear missiles to evade US missile defenses. This, however, hasn't been spectacularly big breaking news, because it's been a statement batted around by the Kremlin for quite some time.

But the fact that the Russians are supposedly talking about high-fallout weapons in the tens of megatons tells us that the guys in Moscow may be perilously close to losing their goddamn minds over missile defense.

Or even worse, have already gone completely bonkers. VICE News reached out to Dr. Jeffrey Lewis, one of the pointier heads in all of nuclear wonkdom to get his take on whether the Russians were going to lose their minds. His response: "Lost. They have fucking lost their shit."

Now, losing your mind is one thing, but considering the fact that professional nuclear planners in both countries are paid very good money to be professionally paranoid, majorly wigging out over nukes is bound to get the other paranoiac to freak out as well, leading to a feedback cycle of arms-race madness that the world thought it left behind when the Berlin Wall came down.

This kind of long-distance, underwater nuclear strike capability may well give US planners an attack of the vapors. Washington, DC, and the US's big naval (and particularly ballistic missile submarine) bases are all on the coast. Thus, this underwater weapon starts to look like part of a first-strike package that could take out a lot of US nukes and stun US nuclear command and control long enough for stealthy nuclear-armed cruise missiles to fly in and strike targets far, far inland, surgically eliminating the US's ability to carry out a prompt retaliatory strike, after which terms and conditions could be dictated.

But there's nothing in that scenario that makes multi-megaton salted warheads a sensible idea. Would the Russians want to try to disrupt rebuilding or retrieving valuable objects from the blast areas (anything from nuclear warheads at a naval base to artifacts from the Smithsonian) just to be dicks about annihilating a coastal city? Or maybe this is just intended to be a revenge weapon of some type. But if it's a revenge weapon, it begs the question of whether the Russians are crazy enough to think that doomsday revenge devices are even worth discussing. And if the Russians are really that wound up, maybe they'll get so agitated that they actually shoot first.

Thinking like this will, of course, prod US nuke planners to get all nutty and start beefing up their defenses. They'll do this by developing systems that are, for instance, intended to spot incoming cruise missiles. And lo, the conditions grow ripe for a new nuclear arms race.

Now, before anyone heads out to dig their fallout shelters, there are a few reasons to be a little bit calmer than the Chicken Littles of Armageddon. For starters, there's the idea that Putin deliberately let news of that concept weapon sneak out into the public media. If that's the case, it could be taken as a desperate desire of Russia to waive off the US by letting the world know that they are able and willing to hold their own in a nuclear arms race, but would rather not start one.

On the other hand, regardless of what Putin did or didn't intend with respect to that system, the US is starting a big, long program to revamp much of its nuclear arsenal. That includes the recently awarded contract for the Long Range Strike Bomber, replacement of its fleet of ballistic missile submarines, and talks (in the early stages) about replacing (or refurbishing) its arsenal of land-based nuclear missiles stashed in hardened silos. It's pretty likely that the Russian nuclear planners will see these replacements (necessary or not) as provocative.

Consider the fact that some Russian thinkers view Obama's regular pitches to reduce the total number of nuclear weapons as a roundabout way of reducing the size of the Russian arsenal enough that the US missile defense system can easily block a counterattack. It's highly unlikely they're going to see replacement of all the US's nuclear delivery vehicles with anything other than outright suspicion.

Still, nobody in Moscow or Washington old enough to remember the Cold War wants to relive several decades of mushroom cloud-shaped existential angst. So it's entirely possible that cooler heads may yet prevail. Nobody has started an arms race yet. But it's not super hard to see how an arms race could come out of all this posturing.

The thing to keep a really, really close eye on is strategic signaling by the US and Russia. Watch to see who is sending what messages when and how. It might involve unusual test-launches of nuclear missiles. It might be reflected in nuclear force modernization decisions. It's too early to know for sure, but in the worst case scenario, we could all be looking at a world in which new, destabilizing nuclear weapons become abundant and belief in mutually assured destruction has significantly eroded. So, even if it's not time to dig a fallout shelter, buying a shovel might not be entirely insane.

Follow Ryan Faith on Twitter: @Operation_Ryan