A job can subtly warp your judgement so that you only see things from one perspective.

Think of Richard Nixon trying to use the institutions of the American government to shut down the Watergate scandal. Or the unexpectedly long American war in Vietnam.

Effective leaders are able to manage both the day-to-day issues that press in on them and the bigger picture. A knowledge of history shows patterns amidst all the noise of current events and reminds of unusual possibilities.

Bismarck famously said that a statesman “must wait until he hears the steps of God sounding through events, then leap up and grasp the hem of his garment”. And he did that when he manoeuvred across the chess board of Europe to create the new state of Germany.

Choosing good and independent subordinates and listening to them is a safeguard against making bad decisions.

In the Cuban Missile Crisis, President John F. Kennedy insisted on hearing his advisers’ different points of view before deciding how to deal with the Soviet challenge in Cuba. 

That means above all understanding your audience and targeting your speech.

Winston Churchill and Pres. Roosevelt masterfully used their communication skills to prepare and keep their nations in a war that at times seemed hopeless.

The people to keep on side can vary: in a democracy, leaders need to worry about who's important in their context.

Bismarck sought to keep a stable relationship with Wilhelm of Germany above all, while the Democratic Party in the USA rose to power by seeking the support of different racial and economic groups.

Leading can be gratifying but also lonely. Ambition and the determination to succeed may mean sacrificing friends and family.

Think of how many children of great men have had unhappy lives. That loneliness is why statesmen like summits: they meet those rare others who face the same pressures and responsibilities.