In the first half​ of the 19th century radical reformers argued that Britain needed three things if it was ever going to become a real democracy: secret ballots, universal suffrage and annual elections. We got the ballot; we eventually got the suffrage; but in an age of fixed-term five-year parliaments, annual elections are as remote as ever. Nineteenth-century democrats knew that having an election every year would be clumsy and time-consuming (the US House of Representatives, which does it every two years, is proof of that). But they thought the alternatives were probably worse. Without regular elections politicians would drift into self-serving cliques that pursued their own interests at the expense of everyone else’s. The only way to hold them to account would be to empower self-styled tribunes of the people to interrogate them before the court of public opinion. That meant democracy would become dependent on adversarial journalism. The danger here was that puffed-up journalists would turn into a self-serving clique of their own.

That is the world we live in. Our tribunes are no longer the sanctimonious hacks of the scandal sheets, like Trollope’s Quintus Slide, the hateful editor of the People’s Banner in the ‘Palliser’ novels. Instead we have deeply entitled TV and radio interviewers whose job is to put politicians on the spot and try to catch them out. They all have their own style. Andrew Marr’s Sunday show regularly ensnares the big beasts. Marr is courteous, intelligent and always sniffing out hypocrisy. How exactly are you any better, is the question behind most of his questions. Evan Davis on Newsnight is even more courteous and if anything even more condescending.

At the other end of the scale is Nick Ferrari on LBC, host of the phone-ins Call Clegg and Ask Boris, who alternates between chummy complicity and violent outrage, often abruptly switching from one to the other, prompted by what he takes to be egregious violations of common sense. John Humphrys on the Today programme can be almost as angry but is more jocular, usually sounding as though he is just one more idiocy away from an uncontrollable guffaw. The interrogators are not all men – Emily Maitlis and Kirsty Wark on Newsnight, and Sarah Montague and Mishal Husain on Today – but the men set the tone.

Looming behind them all is the ghostly presence of Jeremy Paxman and what he said was the unspoken question in any political interview: why is this lying bastard lying to me? The reason journalists think like this isn’t that they have an unspoken political agenda of their own, something they think the politician ought to be saying. It’s simply a question of power v. power. The prize for which both sides are competing is the right to plant their flag on some small piece of territory within the vast domain of informational space. The battle is won by the person who sets the agenda for the next day’s news. A gaffe, a scoop, a soundbite, a rebuttal: these are the spoils of victory. In this arms race, Paxman’s question is entirely reasonable. Any sign of weakness on either side will be taken as an opportunity to exploit. No one comes out well from a political interview by searching for the common ground.

The result, of course, is deeply unsatisfactory for everyone, including the journalists and the politicians. Mutual wariness gets in the way of anything truly revealing being said. Even the most neophyte candidate has been trained in the ways of avoiding a question: fob off the one you’ve been asked with a platitude, stick to your message, and answer the question you’d like to have had put to you. (At Cambridge we now have a course in public policy and these students, most of whom don’t want to go into politics, are trained in how to handle a grilling from an adversarial journalist. Rule one: don’t try to answer the question.) Game theory helps explain what’s going on here. It’s a classic prisoner’s dilemma, in that the outcome that’s best for both parties – in this case, a real conversation – can’t be achieved because in the absence of mutual trust it is rational for each side to pursue its own best-case scenario, a cheap victory, even if it leaves them both worse off. No one wants to be the mug who played fair when the other guy was still trying it on.

One thing that seems particularly to annoy viewers and listeners is the constant interrupting that breaks up the flow of any exchange. This is a game too: a game of chicken. (There’s an archetypal game of chicken in Rebel without a Cause when James Dean’s character agrees to settle a dispute with a local gang leader: both men will drive their cars towards a cliff; the one who jumps first is the chicken.) Interviewers know that politicians will keep spinning them a line unless they can do something to knock them off balance. But they also know that the audience dislikes a shouting match. So the game is to see how long either speaker can hold the microphone, daring the person on the other side to stop them: interruption is the equivalent of blinking first. What makes it a game of chicken is that the player who never interrupts will get run off the road (just as the driver who never turns the wheel eventually goes over the cliff, as happens to Dean’s rival, whose coat gets caught in the car door). You can almost hear the calculation at work in any John Humphrys interview with a leading politician: he is not so much listening to what is being said as listening for the moment when he can bark over the top of it without seeming to be the spoiler. As in any game, process matters more than content.

What this election has shown is that we now also have the game within a game of exploiting our mutual awareness of how poorly the process serves anyone’s interests. On the Andrew Marr Show recently the greyer-than-grey foreign secretary, Philip Hammond, refusing time and again to be drawn on questions about Britain’s defence budget, said to his tormentor: ‘An unguarded comment and people like you tear us apart.’ Then there was the meta-kerfuffle that attended the attempt by the Green leader, Natalie Bennett, to launch her party’s manifesto. She came unstuck during an interview with Nick Ferrari on LBC, during which she started spluttering and coughing to cover up her inability to answer a question about how she would fund a commitment to build half a million new homes. As Ferrari pushed her to explain the finances in terms anyone would understand (‘500,000 homes? £2.7 billion? What are they made of: plywood?’), she was increasingly unable to say anything at all, allowing him to smother her with solicitude (‘Are you all right?’ ‘Yes, sorry, as you can probably hear I’ve got a huge cold.’ ‘I am terribly sorry to hear that’). Bennett quickly had to do the rounds of the other broadcasters to apologise for her excruciating performance (she said it was a case of ‘brain fade’), before the commentators piled in to decide whether any politician – even a fringe player like the Green Party leader – could survive an honest admission of not being able to play the game. The consensus was that it would be nice to think she could. But that would mean everyone else agreeing to suspend the rules of the game. Which meant she couldn’t.

By the time the story reached Newsnight that evening, Evan Davis was questioning the former chair of the Green Party, Jenny Jones, about her own decision at a press conference earlier in the day to try to shield Bennett from having to discuss her failure to answer Ferrari’s questions. Davis quickly got Jones to admit that this too had been a mistake. Davis prefaced this depressing interview with a brief statement in which he explained, as an economist, what Bennett should have said about the finances of house-building. There was a perfectly straightforward solution, which involved borrowing the large sums of money needed and then using the rents from the new builds to pay off the interest (‘Property development can be a profitable business, which is why so many rich people do it,’ Davis helpfully explained). This was perhaps the most absurd moment of all. Davis was talking as though behind every political interview a reasonable technocratic policy discourse was waiting to get out. Not only does this entirely misrepresent what Ferrari was up to (‘More debt!’ he would have shrieked. ‘Turning into property developers are you?’), it also assumes that any politician should be able to agree on the technically correct answers to the questions that interviewers put to them. But of course they can’t, because politics gets in the way. That’s why Bennett was tongue-tied. There aren’t any ready-made answers to the questions that get asked.

An impending election does at least give the interviewing game some point. Knowing there is a vote coming up puts both sides on their mettle. There is more caution, of course, more fear of the fateful gaffe, but also more urgency, which provides some opportunities for questions of substance to cut through the game-playing. We now know that the Greens think the country needs another half a million homes, something that wouldn’t be true at any other point in the electoral cycle. Process can’t entirely dominate substance when an external check holds the politicians to account for what they say and do. Elections perform that function. But once every five years isn’t often enough. If you discount the two world wars, when democracy was effectively suspended, the average time between elections during the 20th century was once every three and a half years, which seems about right. Too much hangs on this election, because there are too few other opportunities to put the interviewers in their place.