Years ago I attended a talk given by the MORI pollster Bob Worcester, who told a story about a briefing he gave to the Labour shadow cabinet in the 1980s. Worcester explained to the assembled politicians that most of the time, they were wasting their time.

The majority of voters were already committed to one party or the other, and so it didn't make sense to target all voters with the party's messages. In fact, the UK's first-past-the-post system meant that only a few voters within a few constuencies really mattered - a number in the tens of thousands.

Worcester said that when he reached this part of his presentation, he heard someone around the table splutter. It was the shadow chancellor, John Smith. "If it's that few, can't we just bribe them?".

It's an axiom of modern politics that, at any one time, only a small number of voters are persuadable. Mitt Romney, speaking in private to an audience of, presumably, the already-persuaded, famously declared that 47% of the electorate would never vote for him. He also said that there were only 5-10% of voters who were open to moving across the partisan divide. Although candidates aren't supposed to speak this way, Romney wasn't actually saying much that a political strategist would find controversial.

But are voters really as locked into their views as modern political professionals assume? The political scientist Morris Fiorina has proposed that the polarisation of America's electorate is a myth. What's really happened, he argues, is that America's political parties have become more partisan and more extreme, and voters have had no choice but to choose between them, even though most retain a high degree of ambivalence and open-mindedness on the issues.

A recently published study from Sweden offers fascinating evidence that voters aren't as fixed in their attitudes as is commonly assumed. Like the U.S., the Swedish electorate is regarded as one of the most polarised in the world, albeit a step to the left overall. In 2010, when the Swedes (like the Brits) last held a general election, pollsters estimated that only about 10% of voters were undecided between the two coalitions competing for office.

In the run-up to the election, the researchers asked people in the street if they would fill in a questionnaire concerning their views on political issues. Participants were asked to indicate how certain they were of their political views, and their current voting intention, from extremely certain social democrat/green, to extremely certain conservatives.

They were then asked to indicate their positions on twelve salient political issues on which the coalitions held opposing positions. For example, "Gasoline taxes should be increased" or "Healthcare benefits should be time-extended". In collaboration with the participants, the researchers then tallied an aggregate score, indicating which political coalition the participant favoured, based on their responses to the policy issues. Finally, the participants were asked to indicate, once again, their voting intention for the upcoming election.

All reasonably straightforward. But here's the clever bit: one group of participants were tricked. While they were filling out the questionnaire, the researcher surreptitiously filled out another form with a pattern of responses that you would expect from someone of the opposite political affiliation, mirroring the skew of the respondent's answers but from the other direction. Using a sleight-of-hand, the researcher then attached this manipulated profile on top of the participant's original answers.

So when it came time to explain and justify their answers, the participants were doing so off a sheet that showed answers that were different to the ones they actually had given. If they previously thought the gasoline tax should be raised, they might be faced with explaining why they had indicated that it ought to be lowered.

The researchers' overall aim was to shift the participant's entire score into the opposite column, so that a left-wing coalition voter would end up with the profile of a right-wing coalition voter (imagine a confirmed Tory ending up with a political profile that indicated she was a strong Labour voter).

During the discussion stage, the participants were free to change their answers if they felt they didn't reflect their original opinion, and sometimes they did so (they would assume they had misread the question or marked the wrong end of the scale). If they did so consistently, they would nullify the the researcher's effort at shifting them to the other coalition.

Remarkably, however, the participants subject to this trickery didn't, for the most part, notice the apparent inconsistencies in their answers. Nearly half didn't correct any at all and most only corrected a few. Instead, many accepted and even justified, with apparent sincerity, opinions which were the opposite of the ones they originally held, or close to it.

Most strikingly, most participants ended up endorsing overall political profiles that put them in the opposite camp to the one they thought they were in, and many changed their voting intention. 19% went from expressing certain support for one coalition to becoming undecided. A further 10% moved across the full ideological span, from firmly right wing to firmly left wing. In total, almost half of these participants were willing to consider a shift from one coalition to the other (compared to the 5-10% that are usually thought to be persuadable). In a few minutes, the researchers had achieved what political leaders spend every day of every year trying to effect.

In one sense, that voters accepted a political profile putting them in the opposite camp wasn't surprising: after all, they thought they were looking at a summary of the answers they had just given. In another sense, it is extraordinary that a person's political identity can be so easily manipulated.

The American psychologist Jonathan Haidt has argued convincingly that political affiliation is primarily about tribalism. Voters align themselves with the parties to whom they feel an emotional attachment, and are adept at inventing policy-based reasons for that attachment after the fact.

The Swedish study is a clever way of circumventing that attachment, because it moves in the opposite direction: it starts by asking voters to reason about policies and builds from there towards party affiliation. That this method can create such radically different results tells us something important about how voters relate to politics.

Politics is a more fluid business than it can appear. As the researchers put it, "the polls can be spot on about what will happen at the vote, yet dead wrong about the potential for change." Voters hold more nuanced positions, and are more open to reason, than the polls suggest or than politicians and the media tend to believe. It's not that voters have their minds firmly made up on the issues that they think their party has got right. It's that they choose their party label and assume that the issues will take care of themselves. But when they are forced to actually the consider the issues, they can be persuaded to change sides. Even without a bribe.

You can read the full study here.

I'm trying to imagine the meeting with American shareholders at which Manchester United's executives explain their choice of successor.

"So you got someone lined up?"

"Yes, we do, and we're very confident in-"

"We heard the Real Madrid guy is on the market. Two European championships, two Premierships, Spanish and Italian leagues. He's the guy, right?"

"Er, no. He's going to one of our biggest rivals."

"Uh huh. So who you got?"

"David Moyes."

"Who's he?"

"He manages Everton."

"Who?"

"Small club. But big ideas!"

"What's he won?"

"Well, he hasn't exactly won anything..."

Personally I think the choice of Moyes is a good one. You can't read this without being tremendously impressed by Moyes's dedication, intelligence, creativity and (relative to resources) success. But boy, it's brave. It feels very much like Fergie's choice, and I wonder if one of the factors pressing him to retire now was so that David Gill, the retiring CEO and Ferguson's closest ally on the board, was still in the driving seat when the decision on succession was made.

But I'm interested in the wider question of why a company like MUFC might choose one kind of manager over another.

From a business point of view, Mourhino would have been by far the safer choice, at least on the surface. You could walk into a meeting with any shareholder and they'd be convinced he was the right guy before you sat down. A proven track record of success at the highest levels, a global reputation, no period of adjustment to the top level necessary: Mourhino would have been the closest thing to a guarantee of success and revenue growth over the next three years. If running a football club is about getting good results quickly, you want the guy who done the most winning in the last ten years.

But a successful business, according to another point of view, depends on more than than short term results. It depends, for its long term health, on something more intangible: call it values, or culture. Ferguson called it history. Whenever a challenger threatened United's dominance, or a player threatened to take a higher offer elsewhere, Ferguson would make reference to his club's history. He returned to it insistently. It was a way of saying, this club is about more than a chequebook, or one season's results, or a balance sheet. It's about values, memories, ethos: things that can't be bought or quickly produced.

It could have seemed old-fashioned and archaic, this insistence, in a world of global brands and profit projections - capitalism has a manic focus on the future, not the past. But Ferguson's focus on history turned out to be good for the business, and good for the club. That shouldn't be a surprise: many studies have found that culture matters. There's a strong link between a company's values and its long term performance. Barcelona and Bayern are examples of clubs whose strong cultures have enabled them to overcome the brutal logic of the market and achieve consistent success on relatively low wage bills. But because it's hard to measure and difficult to create, culture is often forgotten or ignored.

By choosing Moyes, MUFC plc are choosing a culturally based business strategy. Mourhino wouldn't have take as much pride in the club's history or care over its ethos as Ferguson did and Moyes will. Mourhino never really fitted in at Real Madrid, another club with a grand sense of its history, because he is too big a character not to clash with a club with a strong character of its own. He takes his own cultural ecosystem with him: buy Mourhino the manager, and you buy in the Mourhino worldview.This works well at a club at Chelsea, which long ago lost any sense of its own identity. Where there is a cultural void, Mourhino, and perhaps only Mourhino, can fill it.

But that's not the problem at Manchester United. The problem is finding someone talented enough to run the world's biggest football club, and humble enough to know that the club's values are more important to its success than he is.

I am generally quite sympathetic to our politicians, or at least I try to be. First, because it's too easy to blame one group of people for all the world's problems, or to assume that you would behave much differently if you were in their predicament. Second, because the pol-hating game is self-destructive. The more we tar and ridicule our elected leaders, the fewer talented people will want to enter politics, the worse we'll be governed, the more we'll hate our politicians...

Politics is hard. But there are some days when I think, no, there's excuse for this. We deserve - or at least, we need - better leaders than this. 

Yesterday, two incidents, both relatively trivial, brought out the bottle-thrower in me.

The first was David Cameron's appointment of an old chum and St Paul's boy to Number 10. Now, there's nothing wrong with a politician wanting a few old friends and colleagues around him; most Prime Ministers and presidents do the same (those who don't, like Margaret Thatcher or Harold Wilson, never really had close friends to begin with). But Cameron takes it to a new level. When I picture Cameron's Number 10, I see a cramped, fetid male locker room full of chaps boasting about bowling figures and attacking each other with wet towels. Unfair, I'm sure: I'm not doubting that Christopher Lockwood and Jo Johnson are committed and talented. But you might have thought there are some people of similar calibre who didn't go to St Paul's or Eton, and who aren't men. You might have thought the PM would actively seek out people who are different from him. But no. Cameron's defence of his decision is abysmal:

"I judge people by what they can do, what they can bring – by the quality of their brains and the passion in their hearts, not which school they went to."

In other words, the only people of merit went to a small number of public schools. Perhaps he should start considering where people went to school, instead of reverting to innate laziness and unexamined prejudice. A hundred historical examples and social science experiments have demonstrated that even a group of brilliant individuals will make stupid decisions when they suffer from a lack of diversity. How can Cameron not grasp this point, or the secondary one that he is sending entirely the wrong signals to an electorate that already thinks of him and his cabinet as a group of comfortably secluded toffs?

So, to the alternative Prime Minister. Yesterday Ed Miliband gave an interview to Martha Kearney on the World At One that was widely and rightly regarded as disastrous. Partly this was a question of tone. Here's Peter Kellner writing in The Times (£):

The Labour leader sounded shrill when he should have been statesmanlike, tetchy when he needed to be calm, lightweight not mature. As a result his carefully thought-out arguments will have made little or no impact.

I would agree with all that. Sometimes, you can really tell that Miliband was raised in an academic household, in which complex intellectual issues were thrashed out over Corn Flakes. At one point, he asked Kearney a question as if testing her (Kearney waited for a second before replying, coolly, like a teacher to an over-excited sixth form student, "You tell me"). At another he cried, "You don't understand, Martha". And pass the milk.

If Cameron is surrounded by an overly homogeneous clique, so is Miliband. In the latter's case, I suspect the problem isn't that they went to the same school so much as his advisers all come from a similar intellectualising milieu, in which an ability to wield airy abstractions is over-valued and the consensus is that if an interviewer or a voter isn't agreeing with you it's because they just don't understand. Perhaps we will all catch up. Perhaps not.

Then again, how clever do you have to be to see that since you are going to be asked the same question again and again, you'd better have an answer ready? Kearney asked Miliband thirteen times if he intended to borrow more, and every time he evaded the question, mumbling something about "the medium term". Kellner is actually being too kind when he refers to "carefully thought-out arguments".

Miliband and his team must know that until they have a way of dealing with this question, then everything else they have to say will be ignored. I realise it isn't easy. "We're going to borrow more in the short term so that we're borrowing less in the longer term" is a mouthful. But it, or something like it, is the least bad alternative. Until he and the other Ed agree a line, then Miliband is walking out to every crease with his bat broken. 

Now this, I really don't understand. How, after three years to think about it, can you not have an answer ready?

Politics is hard. But Cameron and Miliband are making it look impossible.

Excellent: