Hardly a day passes without public lamentation about the paucity of leadership in the western democracies. Where, cry a score of the nations’ pundits, is a Churchill, Kennedy, De Gaulle, Adenauer for our generation? As a biographer of Churchill, I answer that question partly by saying: be grateful that, however turbulent our times, they are not so dire as to demand his resurrection. Warriors are usually unsuited to addressing social and economic issues. Wellington, the great commander, was a disastrous prime minister, while Churchill’s response to Britain’s 1926 General Strike was histrionic and divisive.

Many contemporary leaders must suffer spasms of self-pity at being in charge during an era when exposure of the limits of power makes high office seem unrewarding. Today’s economic problems are vast and intractable. Contrast the 1990s experience of John Major. Almost as inadequate a British premier as Gordon Brown, he faced many embarrassments and humiliations – recession, ejection from the European Exchange Rate Mechanism, the Balkan wars and Tory strife over Europe. Yet with hindsight, none of these were remotely as dangerous to Britain as recent events. Mr Major’s shortcomings did not matter that much – on his watch, the country suffered no game-changing crisis on the scale of the 2008 banking collapse and what has followed.

The same might be said of Bill Clinton’s US presidency. Though there were plenty of dramas – some of his own priapic creation – nothing tested him as Presidents Roosevelt, Kennedy and Johnson were tested, and as President Barack Obama is being tested now. Some national leaders also enjoy luck: Margaret Thatcher generated much of her own weather, but her exchequer benefited from the North Sea oil boom too.