With the 2020 presidential election approaching, America is bracing to choose its next leader in a time of incredible change and upheaval. How can we recognize the kind of person we’ll need to lead us through these turbulent times? What are the qualities that a truly great American president needs? What can this person, regardless of political affiliation, learn from leaders of the past?

Energy

Many of the greatest leaders in history have been workaholics—Churchill is perhaps the most famous, though Margaret Thatcher, Helmuth von Moltke the Elder, and Marshal Ivan Konev are other examples. Churchill melded his life entirely around his job during the Second World War, taking only eight days’ proper holiday in the whole six years of conflict, six of those spent fishing in Canada and two swimming in Florida, but even on the latter trip he was attended by his red ministerial boxes and he read all the newspapers. Similarly, he was able to work almost throughout his two major bouts of pneumonia during the war. Energy is an almost demonic attribute, hard to characterize, and takes many forms. Churchill was undoubtedly energetic, and yet he often did not get out of bed until noon—and that was for a hot bath—although he had been hard working on his papers since before breakfast. “Concentration was one of the keys to his character,” recalled James Stuart, Winston Churchill’s chief whip. “It was not always obvious, but he never really thought of anything else but the job in hand.”

Ability to plan—and Adapt

A leader’s ability to plan meticulously is important, despite Moltke’s dictum that few plans last beyond the initial contact with the enemy. “Plans are worthless,” agreed Eisenhower. “Planning is everything.” It is often forgotten that one of the most successful war plans in modern history—Hitler’s blitzkrieg against the West that succeeded in knocking out France, Belgium, Luxembourg, and Holland in six weeks in May and June 1940—was not the original one. When the first set of plans fell into Allied hands by accident only days before the assault was due to be launched, Erich von Manstein drew up a new one. It was this plan B that featured the famous sickle-cut maneuver, in which concentrated armor cut the Allies off from their supply bases, the Maginot Line was skirted, the mountainous Ardennes forest—hitherto thought impassable—was used as a conduit, and the Germans broke through at Sedan in six days and reached the Channel coast at Abbeville in only ten. Few plan Bs in history have been so successful.

A Great Memory

For planning in particular and for leadership in general a good memory is useful, or failing that an excellent filing system. Churchill had a photographic memory, and not just for music-hall songs and Shakespeare. He would spend up to thirty hours memorizing his speeches and constantly practice them to make them word perfect, and would even make up ones he was not about to give but might be called upon to deliver sometime in the future. On occasion he would regale his entourage with speeches he would have given if he had been in the House of Commons at different periods of history. For a superb filing system one could hardly do better than Napoleon, who also had an excellent memory and who used his chief of staff, Marshal Berthier, to ensure that even in a carriage rattling along at full pace they were able to place geographically every unit in his army and send and receive messages as aides-de-camps rode up to the windows, grasp orders thrust through the windows, and rode off again to deliver them.

Luck

Although impossible to quantify or predict, leaders need to be lucky as well as brilliant. Before he appointed anyone to the marshalate, Napoleon also wanted to know whether his generals were lucky, and luck undoubtedly does play a large part in war leadership. The role of chance and contingency in history is worthy of an entire book in itself and undermines the Whig, Marxist, and Determinist theories of history in which mankind’s progress through time are set on any definable tramlines.

Understanding Public Sentiment

A great leader has to appreciate the political and economic terrain over which he is to campaign. Franklin Roosevelt might have wanted to bring the United States into World War Two earlier than he eventually did—such was the isolationist sentiment at the time—but in the 1940 election he still had to make his promise in Boston to American parents that ‘your boys are not going to be sent into any foreign wars,’ in order to retain the White House and face the storm that was to come. A leader has to be a realist, albeit one who appreciates the precise moment when it is possible to change public sentiment. In the event of course there was nothing foreign about the war that the Japanese unleashed on America in Hawaii on December 7, 1941. FDR had kept to the letter of his campaign promise.

In this area, Abraham Lincoln was also a supreme war leader, easily the equal of any of the nine in this book. His almost preternatural sense of what the Union would be able to accept politically, and when it would accept it, of what he could ask for and what he simply could not at any particular time, and his willingness to ride political storms, do necessary deals, sack underperforming or disloyal generals, and employ oratory of the Periclean quality of the Gettysburg Address and the two inaugural speeches, makes him second to none as a war leader in the American pantheon.

“Well-timed Unreasonableness”

“The reasonable man adapts himself to the world,” wrote George Bernard Shaw in Man and Superman, “the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.” A talent for well-timed unreasonableness is another attribute of the great leader. Queen Elizabeth I refused to name her successor despite continuous prompting from her Privy Council, thus protecting her country from the danger of civil war. She also refused to ratify the Treaty of Edinburgh early in her reign, despite the pleadings of her closest counsellor Lord Burghley, until the threat posed by the dukes of Guise had finally diminished. Elizabeth I had many of the attributes of a great war leader, in her oratory, in her determination and as a fine picker of men.

Steady Nerves

Having steady nerves in a crisis cannot be underestimated, but can be learned. Basil Liddell Hart wrote in his 1944 book Thoughts on War that “the two qualities of mental initiative and a strong personality, or determination, go a long way towards the power of command in war—they are, indeed, the hallmark of the Great Captains.” Although Stalin had something approaching a mental breakdown when he heard about Operation Barbarossa on June 22, 1941, retiring to his dacha for days as the Red Army and Air Force were pounded on every front, by mid-October, when the Germans were at the gates of Moscow, his nerves had steadied enough for him to stay and fight it out. Charles de Gaulle’s behavior on August 25, 1944, when he attended the service of liberation in Notre-Dame while bullets were being fired within the cathedral itself, also showed rock-steady nerves. Margaret Thatcher during the Falklands crisis and after the IRA assassination attempt on her in October 1984, and Churchill throughout World War Two should similarly complete self-control in crisis moment, just as Napoleon had when his army retreated during the early stages of the Battle of Marengo. Such calm under pressure is the very quintessence of leadership.

Inspiring Persistence

In October 1944 Patton defined leadership as a capacity for “telling somebody who thinks he is beaten that he is not beaten.” As wars are won by the victor of the last battle, the capacity for inspiring the losers of the penultimate battle is key. Here, the sheer doggedness of George Washington stands out supreme, alongside that of Churchill in 1940. Aside from the evacuation from Brooklyn across the East River in August 1776—where a weird combination of low mist and adverse wind direction somehow prevented the Royal Navy from scooping up a force that was down to only nine thousand—Washington enjoyed few successes in 1775 and 1776. As Churchill said of Dunkirk, “Wars are not won by evacuations,” but, also like Dunkirk, the sheer fact of survival and escape was in itself a victory for the American revolutionaries. Simply surviving the hardships of Valley Forge through the winter kept the cause alive and could not have been achieved without George Washington’s shining leadership by personal example. What Liddell Hart was to call “mental initiative and strong personality, or determination” was personified by Washington in that freezing winter of 1776–77, and in all the other leaders in this book. Except through heredity, one does not become a leader in the first place unless one has a strong personality.

Empathy

Understanding the psychology of others is an important part of leadership. Today it seems to be assumed that in order to lead one’s people one needs to have sprung from them, but that is not the case. Many of those who have exuded leadership ability hail from the leisured or moneyed class of their countries—Alexander the Great, Julius Caesar, Napoleon, Churchill, both Roosevelts, and John F. Kennedy among a long list of them—yet they all had a strong sense of what motivated soldiers and citizens who hailed from backgrounds far further down the social scale. A capacity to empathize is far more important than one’s class background. Churchill was born in a palace the grandson of a duke, went to one of the top schools in the country, and never took a bus in his life, but he could speak directly to the needs of what he called the cottage home. When commanding in the trenches of the Great War, he put his earlier campaigning experience to good use in always trying to ensure the men had their creature comforts, such as beer, fresh bread, and a good postal service to connect them with their families.

Political Awareness

Leaders must have a sixth sense for politics, such as in the importance of having a feel for the coup d’œil, a sense of timing, an aptitude for observation, the gift of working out what is genuinely important as opposed to merely diversionary, a faculty for predicting an opponent’s likely behavior in differing scenarios. Of course opportunism can never be underestimated. “A statesman must,” in Otto von Bismarck’s phrase, “wait and listen until he hears the steps of God sounding through events; then leap up and grasp the hem of His garment.”

Sometimes, of course, having all these qualities is still not enough. Napoleon had a staggering number of impressive leadership qualities. He was able to compartmentalize his mind, plan meticulously with a well-trained staff under Marshal Alexandre Berthier, appreciate terrain and guess what was on the other side of the hill, time his attacks perfectly, exhibit steady nerves to his entourage, encourage esprit de corps, publish inspirational proclamations, control the news cycle, adapt to modern tactical concepts, ask the right questions, and show utter ruthlessness when necessary. His charisma was not artificially created, and until the end he enjoyed remarkable runs of good luck. Above all, perhaps, he was single-minded in spotting the moment when he could exploit a numerical advantage at the decisive point on the battlefield. Napoleon had all of these important leadership traits, but he still made the terrible error at Maloyaroslavets on October 25, 1812, of choosing the wrong direction by which to take his army out of Russia. However generous the sprites and fairies are when they gather around the great leader’s cradle with their gifts, there always seems to be a malicious one present to snatch back one gift from the cornucopia.

If you want to know what will move hearts and command multitudes today and in the future, there is only one thing to do: Study the past. In May 1953 Churchill said, “Study history. Study history. In history lie all the secrets of statecraft,” and the same is true of statecraft’s vital subsection, war leadership. If there is one quality that all the great war leaders possessed, it is that which Lord St. Vincent ascribed to Horatio Nelson. St. Vincent did not much like his fellow admiral personally, but he readily admitted that Nelson “possessed the magic art of infusing his own spirit into others.” Great leaders are able to make soldiers and civilians believe that they are part of a purpose that matters more than even their continued existence on the planet, and that the leader’s spirit is infused into them. Whether it is a ‘magic art’ or ‘sinister genius’ can be decided by moralists, but in it lies the secret of successful leadership.

Adapted from LEADERSHIP IN WAR by Andrew Roberts, published by Viking, an imprint of Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2019 by Andrew Roberts.

Contact us at letters@time.com.