'The adults of today remember Ayatollah Khomeini as a hectoring presence on the TV screens of their childhood.' Photograph: Denis Cameron/Rex Features  You may have heard of Majid Javadi. He is a senior Iranian intelligence officer, implicated in a devastating attack on US soil. His links to the Revolutionary Guards place him at the centre of a nexus of terror and criminality that spans the globe. Ruthless and cold-blooded, he thinks nothing of sacrificing innocents – including his own family – in the interests of power.  Javadi is also fictional. He is the villain in the new season of Homeland, a US drama that plays on post-9/11 paranoia and the clash of civilisations. With spooky timing, the focus of the show has switched from the Arab world to Iran. One has to hope that the hotels of Geneva don't subscribe to Showtime, the network that created Homeland. The image of Javadi would be a very bad one for either side in the negotiations over the nuclear question to dwell on.  But the fact that most Americans find a psychopathic Iranian official eminently plausible is relevant to this week's discussions. The shadow cast by the hostage crisis is an especially long one, and the adults of today remember Ayatollah Khomeini as a hectoring presence on the TV screens of their childhood. The Islamic Republic has become a classic bogeyman: an unfathomable evil, of the kind that occasionally pop up in the world to do the righteous harm. It is arguably this two-dimensional view of the country – and the sense that its leaders are not rational actors, but irrational zealots – that has made it so easy for Congress to throw sanctions at the problem, and to dismiss Iranian assurances it does not intend to acquire nuclear weapons as utterly empty.  Although many ordinary Iranians admire and consume US culture, from fast food to satellite TV, the Islamic Republic has also done its fair share of demonising. America is the "great Satan" and no one who has been to Tehran forgets the murals – in one, the stars and stripes are replaced by silvery skulls and lines tracing the paths of bombs falling from the sky. But whereas the roots of America's mistrust of Iran are widely recognised, the reverse is not true. Few Americans are aware of the 1953 CIA-backed coup that replaced Iran's reformist prime minister with a military dictator. Every Iranian is.  Likewise, American support for the shah, and his brutal secret police, Savak, is not thought particularly relevant in Barack Obama's America. If anything, those were the good old days, when the two countries enjoyed an especially close relationship. This nostalgia is reflected in the plot of Homeland. Javadi was once a good guy: back in the day, he and the director of the CIA, Saul Berenson, were rookie case officers together – with Javadi working for the Shah. Saul's job is to win him back, thereby erasing 30 years of history.  That said, the fact that the Geneva talks are happening at all is testament to a new spirit of pragmatism. At the highest levels, the political scene is set. On the one side is a democratic president, free of the baggage of "axis of evil" rhetoric and the hardline influences of Donald Rumsfeld and Dick Cheney, who torpedoed a grand bargain the last a time around. On the other is a newly elected leader given latitude by Ayatollah Khamenei to agree a sanctions-busting deal. And there have been attempts, too, to influence both populations directly. Inspired, perhaps, by Obama's early efforts to speak to Iranians (he broadcast the first ever presidential Nowruz message in 2009) the Islamic Republic has recently been showing it cares about how it is perceived in the west. Hassan Rouhani's English Twitter feed is remarkably informative (it broke news of David Cameron's phone call to the Iranian president before No 10 had issued a press release). On Tuesday the foreign minister released a YouTube video explaining his country's position vis a vis nuclear technology. The supreme leader even has an Instagram feed. Whether these efforts will be able to obliterate memories of angry ayatollahs – or even truculent former presidents – remains to be seen.  One thing is certain: while Saul might succeed in recruiting Javadi, in the real world the clock cannot be turned back. It is vital that Americans finally make an accommodation with Iran as it is, establishing a relationship based neither on exploitation nor wilful incomprehension. The bogeyman must die.
David Shariatmadari: As negotiators gather in Geneva, the plot of the American TV drama suggests that Iran and the US still have some way to go to overcome mutual incomprehension