When Newsnight's Emily Maitlis met The Daily Show's Jon Stewart

We are here to discuss the film Rosewater, his directorial debut. It has been sent to me by the PR company ahead of the release date in cinemas on Friday 8th May. And, in keeping with current practice in the industry – as a foil to piracy, they have burned my name across every single frame of the film so I can’t share it. All the subtitles now appear to end with the phrase EMILY MAITLIS – which I admit to him makes for slightly unnerving viewing.

“Yes,” he deadpans – without missing a beat. “Not just your copy, everyone’s. We made sure every single version of that film has EMILY right across the screen.” And my shoulders drop with relief. It is vintage Jon Stewart. His tone. His voice. Suddenly I know it’s all going to be fine.

Rosewater is the true story of Maziar Bahari (played by Gael García Bernal), an Iranian BBC and Newsweek journalist who was thrown into prison for 118 days after filming incriminating footage of the security services during the election of 2009. It was Iran’s “Green Revolution” that brought social media – especially Twitter – to the fore as a powerful tool for telling the world about repressive states and fixed ballots.

So far so simple. But there’s another reason Rosewater feels so personal. Bahari had participated in a Daily Show sketch – a goofy, spoof interview in which he is asked if he’s a terrorist. Once incarcerated, this footage was shown to Bahari and fellow journalists in prison as “proof ” they had been spying for the Americans. So I am wondering, as I sit down with Stewart, on a massive stripey sofa in a completely empty room, whether the film is partially born of guilt.

“Not necessarily guilt,” he tells me. “I think we became involved based on an unlikely connection. Our main concern was that we still had pieces to run and if we ran them, would that put [the imprisoned journalists] in further jeopardy? Their families made clear they wanted more publicity, not less. They wanted to speak of it.”

I’m intrigued by this sense of personal responsibility. After all, I say to him, The Daily Show has always maintained that it’s comedy. It’s entertainment. It shouldn’t be tarred with the news brush. Suddenly, Rosewater seems a million miles from that. One review called it “unabashedly earnest”. A phrase I have difficulty reconciling with Stewart.

“Well, it’s not so much tar with the news brush,” he corrects. “I think that’s somewhat misunderstood. When we say we’re comedians, I don’t mean that we don’t stand behind the voracity of the research. We do. What I mean is, the language of news and the language of satire are two very different things. So they have to be judged on different metrics. In other words, the tools of satire may be a bit of a bludgeon if you look at them journalistically. But we seek to come to some kind of real insight into something through juxtaposition, hyperbole. In the same way a cartoonist might say, ‘I’m a cartoonist.’ It’s not a way of deflecting responsibility for their viewpoint, but as a way of saying, ‘The tools of my trade are of a different essence from yours.’”

The Daily Show, at its most brilliant, has captured moments of America’s soul since the turn of the millennium. Stewart nailed the anger of the economic crisis when he brought CNBC’s moneymouth Jim Cramer to his knees . And, eight years earlier, there was a restrained but curiously moving address to his audience after 9/11: “We’re going to start by asking you at home the question we’ve been asking everyone here in New York, and that is: ‘Are you OK?’”

Viewers see him as a natural Democrat, but he can be just as merciless to those on the left. I remind him of a Daily Show moment I watched from a Washington hotel room on the eve of the mid-term elections in 2010, with Barack Obama as his guest. He asked the President if that totemic campaign slogan “Yes we can” could still be a realistic position. The President’s bathetic response was: “Yes we can, but...”

It was a soundbite that perfectly encapsulated his struggle with delivering what Sarah Palin once called “that hopey changey thing”. So has Stewart been disappointed in Obama? “I know the tendency is to want to make judgements on things – George Bush was this, Obama is this – but it’s a far more nuanced picture than that. It’s not black and white. It’s why we attach the word ‘gate’ to everything. Because it’s a scandal and it involves a politician, we put ‘gate’ on it.”

It’s a diplomatic answer, which perhaps conceals more than it yields. But Stewart’s own political awareness was formed by the original one – Watergate, a seismic moment for a nine-year-old that coincided with his parents’ separation. Events, he now jokes, that have been conflated by his young mind.

“My father resigned at the same time as Nixon,” he recalls. “They both resigned and walked to a helicopter and did that wave.” His father’s “resignation” took the form of estrangement. Donald Leibowitz left the family home. And never saw his son perform. Those looking for an understanding of why Stewart changed his surname may find it here.