Two favourite fictional US vice-presidents have now made it into the Oval Office, but whose would be the safer hands in which to put the nuclear codes: Veep’s hapless Selina Meyer (Julia Louis-Dreyfus) or the scheming Frank Underwood (Kevin Spacey) from House of Cards? And, more importantly than the possibility of Armageddon (after all, box-set addicts will presumably be very content in their bunkers) is the question of how their respective creators are going to keep Veep and House of Cards on the boil, now that Underwood and Meyer are in the top job.

Don’t expect Veep’s Armando Iannucci to become more reverential now that he is dealing with the presidency. For House of Cards show-runner Beau Willimon, however, the problem is different: after all, reaching the top has been the raison d’être of Spacey’s Machiavellian South Carolinan. Willimon remains understandably tight-lipped, but a 45-second trailer for the forthcoming third season features a Putin-alike Russian leader refusing to shake Frank’s hand at a press conference, and later forcefully snogging Frank’s wife Claire (Robin Wright) at an official function. (The Russian leader, Petrov, is played by the Danish actor Lars Mikkelsen, from The Killing and Sherlock.)

Netflix’s more recent three-minute teaser for season three suggests that there will be marital discord between the First Couple, when Claire recoils from Frank’s touch during an official photoshoot. Could Petrov be the cause of this disharmony? Frank and Claire always seemed bound more by the co-dependency of serial killers than by any powerful physical attraction, and that threesome with the bodyguard suggested that Frank might swing both ways. A more brilliant possibility than Claire seeking mere physical solace elsewhere would be to have her outgrow Frank. Now that he has escorted her to the top, is she, with trademark ruthlessness, about to shed her husband? Frank, however devious, usually shares his innermost thoughts with the viewers, while Claire is the enigma of House of Cards. But she drops a hint in a line from episode one of the new season, leaked by The Hollywood Reporter: “I’m almost 50 years old,” Claire says. “I’ve been in the passenger seat for decades.”

The Hollywood Reporter was one of the media outlets that were alert last week to the accidental early online availability of season three – an error that Netflix rectified after only 20 minutes, but not before some nimble account holders had glutted on episode one, along with Netflix’s descriptions of all 13 episodes. These synopses are sketchy and brief, but those who wish to avoid spoilers should still stop reading now…

As glimpsed in the first trailer, Russia is this season’s China; the big geopolitical bogeyman. “The Russian president’s state visit becomes a cold war of wills, and some punks heat things up,” one synopsis reads, leading to the hope that Pussy Riot will put in a special guest appearance. Two members of the anti-Putin band were indeed spotted on set in Baltimore last August.

Another synopsis tells us that “Claire sets her sights on the United Nations”, and it’s cheering to see that her ambition remains as ferociously clenched as ever. One of the questions that House of Cards poses is what its resident ice queen really wants. Is it power, pure and simple? Or to be seen as a great philanthropist? It is the dichotomy of this Lady Macbeth-shaped enigma that her iron will seems directed towards charitable ends.

Or maybe not. According to those who streamed the first episode last week, Claire admits to an ambition to run for public office. It seems we may have a Clinton-esque dynasty in the making – or at least a spin-off series.

Other storylines feature a hurricane that endangers the East Coast, while elsewhere, “The Jordan Valley erupts in chaos”. But it’s not these wider background details that really interest fans; we’re more invested in the show’s characters.

One of those who won’t, presumably, be coming back is Frank’s ex-alcoholic chief of staff and confidant Doug Stamper (Michael Kelly). His unorthodox courtship of waitress and former prostitute Rachel (essentially, he imprisoned her in a one-man witness protection programme) concluded during the season two finale when Rachel bashed him on the back of the head with a brick and drove off in his car.

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With her knowledge of the Peter Russo murder, Rachel (played by Rachel Brosnahan) is sure to play a vital role in the new season. In another leaked line, Claire says to Frank: “Any idea where she is, because it’s important we find her?” A good place to look would be the apartment of church-goer Lisa (Kate Lyn Sheil), as presumably she and Rachel will resume their sub-duvet explorations.

One final rumour, and one that will lie heavily on fans’ hearts, is that the third season of House of Cards will be the last. This suggestion is based on a flimsy premise: that, because the BBC original ended after three series – with the Frank Underwood figure (Francis Urquhart, played by Ian Richardson) being assassinated by his wife – then the US version will end there too.

Nevertheless, the suspicion that Kevin Spacey may soon be spending more time with his movie career (he is currently filming Elvis and Nixon, about a 1970 meeting between Elvis Presley and President Nixon; no guesses which one Spacey is playing) has been lent some credence by Mozhan Marnò, who plays journalist Ayla Sayyad in House of Cards. The ending of season three, Sayyad told Entertainment Weekly, “will be even more surprising than fans expect”.

Personally, I hope Netflix do end it at that point – although you can understand if they don’t – because for Underwood, as well as for the show, the only way thereafter will not be up.

‘House of Cards’ is available to download on Netflix from 27 February