The usual view of history for left-leaning liberals is that the character of the leading protagonists is secondary. The real drivers of history are socio-economic forces. Marxist views of history, which I imbibed as an undergraduate, take this further: history is determined by material conditions – wages, working conditions, social relations. But in moments of crisis, such as the EU referendum and its consequences, personality flaws really do matter. When events are finely balanced, what this or that individual does can make all the difference.

The consensus about the Brexit vote is that it expressed resentment about how politicians had driven forward social changes without the consent of the affected communities. So social forces were certainly important. But in an extraordinary year where the right gained the upper hand and effective opposition disintegrated, what’s striking is how many fatal twists and turns were set in motion by misjudgments based on the character flaws of the leaders. Without the hubris, arrogance, laziness, disloyalty, connivance and opportunism of so many of the key players, we would probably not be in this current state of Brexit-induced political mess.

How far back should we go with this idea that misjudgments based on character flaws led directly to this mess? A long way. Tony Blair’s hubris about the Middle East discredited his centre-left politics. The fratricidal competitiveness of Ed Milliband helped to deprive Labour of victory and a platform to rebuild the centre-left. Also key in the 2015 election was Nick Clegg’s duplicity around student fees. His class chemistry with David Cameron and his evident liking for his position caused him to massively disappoint his voters – a move that in effect wiped out the Liberal Democrats.

This left Cameron unchallenged except by his own right wing. And of all the personality flaws in this saga, his proved the most glaring. His laziness and lack of attention to detail, characterised by the press as “Dave’s chillaxing”, made him supremely confident about the referendum. He thought he could face down the right relying on electoral “reasonableness”. This relaxed attitude was fatal. The stakes were too high, and the details about the referendum’s status really mattered, as the ensuing muddle revealed. Cameron’s failure to see danger coming allowed a motivated right wing to define the agenda.

The weeks following the vote was a period many commentators described as a Greek tragedy, which is all about character initiating a fatal sequence of events. Michael Gove and Boris Johnson appeared motivated more by manoeuvring for leadership than deep conviction, as well as being deluded about their own strategic cleverness. But Johnson was rather too good at connecting with the popular mood, at turning the perfect phrase, at echoing and, to some extent, manipulating the popular press, and got the result he almost certainly didn’t want. His stricken face on Brexit morning suggested he had really sought to be the “unifying” leader in a close remain vote. Gove’s downfall came from opportunism, disloyalty, and an overestimation of his ability to outmanoeuvre Johnson.

Of course politicians’ characters are always crucial factors in determining the direction of events, and politicians by nature probably have a larger dose of personal ambition and cunning than the average citizen. In robust circumstances when political checks and balances are working well, where attention is given to detail, and where a strong opposition is able to articulate public concerns, then leaders’ character traits and even flaws don’t matter so much. But the Brexit negotiations are finely balanced, and the public is being offered little chance of scrutinising decisions.

The current leaders look even more flawed than those whose misjudgments led us to this point. We now have a secretive and controlling prime minister in charge of the biggest team of negotiators to be assembled since the 1945 peace conferences. For a negotiation unwanted by a significant proportion of the electorate, who need to be won over, it doesn’t inspire confidence.

Meanwhile, Jeremy Corbyn in opposition seems the embodiment of a flawed character. His vanity prevented him from turning down the leadership, a position for which he was clearly unsuited. In less uncertain times, Theresa May’s control freakery and Corbyn’s inflexibility might not matter. But they matter when what’s needed are leaders who can see the wider picture. Policies are vital, but character is more important than ever. Start worrying.