Diplomats in Moscow and western capitals may deny that we are seeing the beginning of “Cold War Two,” but the truth is relations are at their lowest point since the end of the Soviet Union.
And the “missing submarine” is most likely guilty of typical Cold War behaviour: spying, or deliberately testing Western reaction.
Sweden may not be a member of Nato, the dark alliance that Moscow’s defence chiefs have identified as Russia’s number one enemy. But it has always taken defence of its “neutrality” extremely seriously.
Its shoreline is still dotted with Cold-War era artillery batteries, and to this day it has one of the most advanced navies in the world - its new Visby class corvettes are widely billed as “the world’s first stealth ships.”
In the relatively small Baltic Sea, that makes Sweden something of a naval super-power, and a neighbour that Russia - which has Baltic ports at St Petersburg and Kaliningrad - would naturally keep a very close eye on.
It might be embarrassing to get caught, but it would be far from surprising to find a Russian submarine servicing underwater spy equipment, perhaps installed during the Cold War, or possibly shadowing Swedish navy exercises.
Testing the Waters
Another explanation is that the Russians actually wanted the submarine to be caught.
With the West and Russia at loggerheads over the annexation of Crimea and Moscow’s proxy war in eastern Ukraine, tensions in the Baltic Sea are higher than at any time in recent history.
Nato has held a series of exercises in the region to let Russia know any attempt to repeat the adventure in Estonia, Latvia, or Lithuania will be met with force.
And Russia has sent its own signals via the crude diplomatic telegraph of “training exercises.”
Last month, the Swedish airforce scrambled jets to see off an incursion by two Russian fighters flying out of Kaliningrad.
Their mission appeared simply to see how far they could get into Swedish airspace before being turned back - part of a Cold War era practice designed to probe a neighbour’s defences and signal that the Russian military is back in business.
Western militaries say such flights have become worryingly frequent, with Britain, the United States, and Japan all scrambling fighters to see off Russian aircraft from their airspace in the past few months.
Sending a submarine to skulk off the Swedish coast may be the Russian navy’s way of keeping up with the airforce - and letting the West know that Russia will not be intimidated in this strategically vital sea.
Then again, as everyone one knows, the best role of a submarine in any Cold War drama is to deliver or extract spies from hostile shores in the dead of night.
Following that logic, the vessel in question almost certainly ran into trouble while delivering a Russian agent to a remote Baltic island to do something swashbuckling and nefarious.
Exactly what such a spy might be up to is anyone’s guess.
After all, Russia and Sweden are not at war, and Aeroflot flies Moscow to Stockholm twice daily (from a very reasonable £73, according to the airline’s website).
So unless Moscow’s spy agencies have lost the ability to travel incognito, there would have to be a good reason to take such a risky and laborious travel option.
Probably the kind of reason that would make a decent airport paperback.
If a Russian submarine really has been stranded off the coast of Sweden, it raises the question - what could it have been getting up to? Roland Oliphant explains
Menacing the West with nuclear weapons
On Sunday, a rumour appeared on Ukrainian Twitter accounts naming the missing submarine as the Dmitry Donskoi - a ballistic missile submarine of Russia’s northern fleet equipped with Russia’s brand-new nuclear-tipped Bulava missiles.
One of the largest submarines ever built, it was implied, had suffered some catastrophic failure and was now stranded somewhere on the Baltic Sea bed, unable to contact Moscow and threatening Scandinavia with a kind of maritime Chernobyl.
The rumour played on memories of the Kursk disaster, when a submarine was lost with all hands in the Barents Sea in 2000.
But it is almost certainly fantasy.
At 175 meters, the Donskoi is almost the size of an aircraft carrier and, in the shallow waters of the Baltic, about as easy to hide.
Whatever is lurking amongst the islands of the Stockholm archipelago, it is not a missile submarine.
* Noticia publicada a The Telegraph. Més enllà dels esdeveniments diaris, cal plantejar hipotesis plausibles, i la del Telegraph ho és bastant.