To begin with the largest relevant facts: we know that Lincoln as president went often to the theater, and we know, from the density of quotations and allusions in his speeches and from the testimony of others, that he had read deeply in the Bible. We might well suppose on similar evidence that his interest in Shakespeare had been strong for much of his life. Yet the only hard evidence of any depth about Lincoln and Shakespeare comes from a letter he wrote in the middle of the Civil War, about six weeks after Gettysburg.

Lincoln had received the gift of a book, Notes and Comments upon Certain Plays and Actors of Shakespeare, with Criticism and Correspondence, from its author, James H. Hackett. He wrote back from the executive mansion, Washington, August 17, 1863:

Months ago I should have acknowledged the receipt of your book and accompanying kind note; and I now have to beg your pardon for not having done so.… Some of Shakespeare’s plays I have never read; while others I have gone over perhaps as frequently as any unprofessional reader. Among the latter are Lear, Richard Third, Henry Eighth, Hamlet, and especially Macbeth. I think nothing equals Macbeth. It is wonderful. Unlike you gentlemen of the profession, I think the soliloquy in Hamlet commencing “O, my offence is rank” surpasses that commencing “To be, or not to be.”

It is an unusually personal letter by Lincoln’s standard, and a couple of details stand out sharply. First, none of the plays that he mentions is a comedy. A far more striking point is Lincoln’s preference for the short soliloquy in which Claudius confesses his guilt, over the meditation on will and action by Hamlet that was already among the best-known passages in all of Shakespeare. Lincoln recognizes that his view is heterodox but he stands by it. Finally, and this is another revelation, he confesses a superlative estimate of Macbeth. “I think nothing equals Macbeth.” Lincoln was deeply touched by the portrait of the mind of a politician who had committed great wrongs. He was not equally moved by the thoughts of a hero who reproached himself for doing too little.

Turn, now, to a general statement by Lincoln on the hazards of political ambition. It comes in an early speech, the Address to the Young Men’s Lyceum of Springfield, Illinois, on the Perpetuation of our Political Institutions, delivered in January 1838. The perpetuation of our institutions was a common topic of such lectures at the time; but Lincoln turned more particularly to the dangers of mob violence, of the “mobocratic” spirit (as he called it) that emerged in a spate of lynchings in St. Louis and Vicksburg. Lincoln takes these outbreaks to be a sign that Americans have never fully separated themselves from the excitable mood that was necessary for winning American independence:

It is to deny, what the history of the world tells us is true, to suppose that men of ambition and talents will not continue to spring up amongst us. And, when they do, they will as naturally seek the gratification of their ruling passion, as others have so done before them. The question then, is, can that gratification be found in supporting and maintaining an edifice that has been erected by others? Most certainly it cannot. Many great and good men sufficiently qualified for any task they should undertake, may ever be found, whose ambition would aspire to nothing beyond a seat in Congress, a gubernatorial or a presidential chair; but such belong not to the family of the lion, or the tribe of the eagle. What! Think you these places would satisfy an Alexander, a Caesar, or a Napoleon? Never! Towering genius disdains a beaten path. It seeks regions hitherto unexplored. It sees no distinction in adding story to story, upon the monuments of fame, erected to the memory of others….Is it unreasonable then to expect, that some man possessed of the loftiest genius, coupled with ambition sufficient to push it to its utmost stretch, will at some time, spring up among us? And when such a one does, it will require the people to be united with each other, attached to the government and laws, and generally intelligent, to successfully frustrate his designs.

It has been argued—notably by Edmund Wilson in Patriotic Gore and by George Forgie in Patricide in the House Divided—that Lincoln’s portrait of a “towering genius” who disdains the level ground of equality and seeks domination really amounts to a confession of temptations that he recognized in himself but could not otherwise reveal. I doubt that this is true. Caesar and Napoleon and, closer to the present, Andrew Jackson, are more likely to have been the examples he had in mind. But it is true that Lincoln was aware of his own ambition as a necessary part of his energy for politics. His junior partner in legal practice and eventual biographer, William Herndon, said that Lincoln’s ambition was “a little engine that knew no rest.” We can call this, if we like, the remark of a junior partner more than of a gifted observer, but we cannot afford to neglect the depth of association that underlies it. Herndon had a daily exposure to Lincoln that few others could claim. But Lincoln in any case did speak consciously, on occasion, of the inward pressure of his love of fame. It is clear from his speeches, writings, and actions that he struggled against ambition in order not to let it prevail over his sense of justice. It was a struggle, and it never ended.

From what familiar political sources might an American of Lincoln’s generation have come to suppose that ambition poses a moral and political danger? A commanding statement on ambition, probably as familiar to Lincoln’s thoughts as any warning by an American, was the pair of speeches by Brutus and Mark Antony to the Roman crowd in Act 3 of Julius Caesar. Brutus speaks there of the assassination in a manner that seeks to persuade by logical and pedantic steps, under strict emotional regulation:

If there be any in this assembly, any dear friend of Caesar’s, to him I say, that Brutus’ love to Caesar was no less than his. If then that friend demand why Brutus rose against Caesar, this is my answer: not that I loved Caesar less, but that I loved Rome more. Had you rather Caesar were living, and die all slaves, than that Caesar were dead, to live all freemen? As Caesar loved me, I weep for him; as he was fortunate, I rejoice at it; as he was valiant, I honour him: but as he was ambitious, I slew him. There is tears, for his love; joy, for his fortune; honour, for his valour; and death, for his ambition.

Now Lincoln, to say it roughly, held sentiments for the American republic and Constitution that were close to those declared by Brutus, but he took constant care not to allow any abstract argument to overcome the moral presumption against the good of killing. And that meant killing in the name of any cause whatever. There had been an outbreak of national and apparently lawful violence, within the span of Lincoln’s own career, that aroused him to direct criticism of the ambition of a president. The event was the Mexican War, which began in 1846, whose progress overlapped with Lincoln’s term in congress from 1847 to 1849. Lincoln’s speech on the floor of Congress on January 12, 1848 addresses President Polk almost directly. “Let him answer,” Lincoln says,

fully, fairly, and candidly. Let him answer with facts, and not with arguments….And if, so answering, he can show that the soil was ours, where the first blood of the war was shed—that it was not within an inhabited country, or, if within such, that the inhabitants had submitted themselves to the civil authority of Texas, or of the United States, and that the same is true of the site of Fort Brown, then I am with him for his justification…. But if he can not, or will not do this—if on any pretense, or no pretense, he shall refuse or omit it, then I shall be fully convinced, of what I more than suspect already, that he is deeply conscious of being in the wrong—that he feels the blood of this war, like the blood of Abel, is crying to Heaven against him. That originally having some strong motive…to involve the two countries in a war, and trusting to escape scrutiny, by fixing the public gaze upon the exceeding brightness of military glory—that attractive rainbow, that rises in showers of blood—that serpent’s eye, that charms to destroy—he plunged into it, and has swept, on and on, till, disappointed in his calculation of the ease with which Mexico might be subdued, he now finds himself, he knows not where…

There are echoes, in this speech of 1848—echoes meant to be heard by Lincoln’s audience—of the soliloquies in which the political assassin Macbeth conjures up images of his own guilt. Those images appear as a phantasmagoria of floating causes, yet, at the same time, they confess the concrete reality of his guilt. Macbeth has pursued an object of dangerous allure beyond the reach of self-understanding. The speech that opens Act 2, which begins, “Is this a dagger which I see before me?”—that speech, for one, throws a shadow forward into actual history in the accusation by Lincoln against a president who seems to have become a usurper. Macbeth is referred to, elsewhere in the play, as an equivocator, and the same epithet by implication is extended by Lincoln to President Polk in his dealings with Mexico and his evasive explanations to the American people. Lincoln’s description of such an adventurer having “swept, on and on,” makes us aware, too, of the resonance in his mind of the words of Macbeth: “I am in blood, / Stepped in so far that, should I wade no more, / Returning were as tedious as go o’er.”

Recent biographers of Lincoln, such as William Gienapp and Doris Kearns Goodwin, have treated his opposition to the Mexican War as a minor episode of his career. I am not sure on what grounds. It required unusual courage for a first-term congressman to make the sustained accusation of which I have just quoted the climactic passage. Its powerful allusion to Macbeth offers a clue to his thinking that seems consonant with Lincoln’s habits of moral reflection generally. He gave full vent to his suspicion of high crimes and misdemeanors. And his judgment in this instance, as on so many later occasions, was guided not by fascination with the glory of heroic virtue but rather by a concern with the causes that may drive an ordinary man to commit deep wrongs.

Can we come any closer to the intuition shared by Herndon and other witnesses that Lincoln knew the workings of ambition in himself? There is significant evidence on this point in one of the unexpected fragments of Lincoln’s notebook. The entry concerns his rivalry with Stephen Douglas. In 1856—two years after Douglas opened the door to the extension of slavery by securing passage of the Kansas-Nebraska Act and the repeal of the Missouri Compromise—Lincoln reflects:

Twenty-two years ago Judge Douglas and I first became acquainted. We were both young then; he a trifle younger than I. Even then, we were both ambitious; I, perhaps, quite as much so as he. With me, the race of ambition has been a failure—a flat failure; with him it has been one of splendid success. His name fills the nation; and is not unknown, even, in foreign lands. I affect no contempt for the high eminence he has reached. So reached, that the oppressed of my species, might have shared with me in the elevation, I would rather stand on that eminence, than wear the richest crown that ever pressed a monarch’s brow.

If Lincoln’s speech on the Mexican War seemed to say that the love of power has an inward drive, an energy that feeds on itself, this note on Stephen Douglas eight years later indicates the origin of that momentum in political ambition. And there is something strangely impersonal, maybe we should say something de-personifying, about ambition. It takes you out of yourself. By its dynamism, you become a name, and the sound of that name may fill the nation and be known in foreign lands: but who is the person under the name? Where ambition takes its full swing, it is as if a break in oneself had occurred, out of the need to acquire fame or power from a force outside oneself, a force that reaches in and pulls without letup or allowance for thought. The person who has become a prey to that force is “swept on and on.”

Ambition then has this peculiarity, that it begins from an egotistical motive, the wish to leave a deep impression on the world; yet the effects of ambition, its momentum and pressure for external aggrandizement and its instrumental use of available objects and other people, all lead away from any proper self or individuality. The lips of the office mumble the words for an act of state no person could ever vouch for. By the changes wrought by ambition, the person disappears into the force-field of the act. For the person captured by ambition, the power of agency increases vastly, while the identity of the actor dwindles to the sum of his effects. The mask becomes the face; and it is a quality of ambition that the person whom it seizes is half aware that this will happen, sees it start to happen, and wants it to go on happening. He wants it even as he may feel that the mask weighs heavily, and even as he regrets that the expression on the face of the actions is no longer his own.

Lincoln seems to have held in view from 1858 the strong possibility of a war over slavery. And, close as he was to abolitionist opinion (though not an abolitionist himself), he must have recognized emancipation as a possible result or consequence of a civil war. To do good for his country, however, meant to avoid war if possible. Yet it may be a thin line that separates conscious prudence from corrupt manipulation—a line that a character like Macbeth or Caesar must cross many times, and that most politicians, if offered the rewards of violent action, will do what they can to erase. A politician strongly tempted has no trouble picturing himself as “a principal actor,” to quote the formulation of Edmund Burke, “weighing as it were in a scale hung in a shop of horrors,—so much actual crime against so much contingent advantage.” Lincoln practiced a more rigorous restraint: there were things he would not do. Still, he came to know the allure of calculations that must present themselves as preliminary to an unjust political action. He had to come face-to-face with such moments if only to reject the temptation.

“The colored population,” Lincoln writes, in a note to Andrew Johnson (then the military governor of Tennessee) dated March 26, 1863, “is the great available and yet unavailed of, force for restoring the Union. The bare sight of fifty thousand armed, and drilled black soldiers, on the banks of the Mississippi, would end the rebellion at once.” The sight, unaccompanied by words, would end the war. Why did Lincoln so seldom jump from such a perception to a sudden decision by fiat? When one searches his principles of action, one sees lines of explanation that lead away from a policy of dictatorial command or deliberate expedience; the pattern, in Lincoln, instead leads back to a radical aversion from injustice. Among the sources of that aversion, I believe, was his reading of Macbeth. Recall his words: “Nothing is equal to Macbeth.”

One speech must have been at the heart of the play, for Lincoln. Macbeth’s soliloquy at the end of Act I is about action, like “To be or not to be,” but it comes from a man who will act with disturbing force:

If it were done, when ’tis done, then ’twere well

It were done quickly: if the assassination

Could trammel up the consequence, and catch

With his surcease success; that but this blow

Might be the be-all and the end-all—here,

But here, upon this bank and shoal of time,

We’d jump the life to come.—But in these cases,

We still have judgment here; that we but teach

Bloody instructions, which, being taught, return

To plague th’inventor; this even-handed justice

Commends th’ingredience of our poison’d chalice

To our own lips….

—I have no spur

To prick the sides of my intent, but only

Vaulting ambition, which o’erleaps itself

And falls on th’other.

Surely when Lincoln thought of this speech, he took it as a warning. Ambition, by its nature, moves from a thought of something that might happen—something one might do and enlarge one’s own power by doing—to the idea of actually improving the odds by creating for oneself the relevant favoring circumstances. So one might banish all second thoughts and commit the wicked deed, and make sure of being so placed as to gather in the benefits to oneself. An accompanying fantasy is that moral effects will cease with the end of the action itself: to “catch / With his surcease success”—the victim’s death and the killer’s triumph seem almost a pun on each other. Death will crown the bringer of death because the two words sound so close.

Thus, in the logic of the passions, a connecting channel is carved out from “I can do this” to “I will do it,” with no intervening prohibition of conscience, no thought of the actual good or harm that will come to others far from the scene. Self-deception also comes in to do its usual work. I say: “This was forced on me—I merely used an opening in the circumstances that anyone would have filled.” Or, alternatively: “How could I know all the terrible consequences at the time of action?” Both of these excuses lie adjacent to the claim concerning a voluntary action, “I did not mean it,” which comes close to saying that I am not I.

Macbeth, and this lies at the heart of his drama, gives up self-sufficiency in exchange for aggrandizement. His self-possession is never stable thereafter; the possession of other persons and other things becomes the substitute. (There lies a residual meaning, perhaps, of the dreamlike phrase “falls on th’other.”) The category of sincerity no longer applies to persons overtaken by ambition. Their words and their thoughts cannot afford to agree. Admittedly, Lincoln might seem to have been explaining away the personal element of his political choices when he said, in a famous and elusive remark about the Emancipation Proclamation, “I claim not to have controlled events, but confess plainly that events have controlled me.” This is, by the sound of it, an evasion in Lincoln, somewhat like the evasions of self-ascription by Macbeth.

But let us not understand him too quickly. His sentence denying control of events, as I read it, is a tactical statement, but it is far from putting off responsibility for the actions of the war. Its sense ultimately is not that he did what history forced him to do, and that anybody in his position would have done the same, because he had no choice. It is rather that he could not have issued the Emancipation Proclamation any time he pleased; he had to wait for the victory at Antietam to gauge a moment when the continued rise of Union fortunes depended on the addition of new recruits; and a moment when, of such recruits, only emancipated slaves offered a large and conspicuous source. So Lincoln is saying: events did play a part in the timing of my judgment, but they did not constitute my conscience. I am I.

Consider once more Lincoln’s fascination with the soliloquy of Claudius in Hamlet. Did he interpret that speech as another warning? I suspect that it was, for him, an actual judgment on himself, as it is a judgment on any person whose conscience is heavy from the knowledge that power has come to him through the sacrifice of others:

Pray can I not,

Though inclination be as sharp as will,

My stronger guilt defeats my strong intent,

And, like a man to double business bound,

I stand in pause where I shall first begin,

And both neglect….

My fault is past—but O, what form of prayer

Can serve my turn? “Forgive me my foul murder”?

That cannot be; since I am still possess’d

Of those effects for which I did the murder,

My crown, mine own ambition and my queen.

May one be pardon’d and retain th’offence?

In the corrupted currents of this world

Offence’s gilded hand may shove by justice,

And oft ‘tis seen the wicked prize itself

Buys out the law. But ’tis not so above:

There is no shuffling, there the action lies

In his true nature, and we ourselves compell’d

Even to the teeth and forehead of our faults,

To give in evidence.

Claudius’s speech is a despairing appeal to heaven by means of a prayer that is not answered. Or rather, the prayer is answered by foreknowledge of the faults that will count as evidence at a tribunal on our deeds—a trial that occurs in this world and not in the life to come. This speech marks a pause in the plot of Hamlet. It is the only clear showing of a person of wicked intent, in a play whose moral bearings otherwise are extraordinarily elusive. Of course, Lincoln, for many reasons, would hardly have associated himself or his political conduct with the character of Claudius—a weak and sensual man who seems to have committed murder for the usual rewards.

Yet it would be characteristic of Lincoln not to want to deny his kinship with Claudius. His interest in the neglected soliloquy in Hamlet belongs to the same honesty of thought that we feel when he admits the resemblance between himself and Stephen Douglas. “We were both ambitious; I, perhaps, quite as much so as he.” Lincoln’s whole political life, most of all his time as president, was directed at avoiding the imposition of his will on others whenever that would involve injustice. Conscience, often if not always, stopped him short of the grand assertions of arbitrary power that the ambitious have no second thoughts about.

A longer version of this essay appears in David Bromwich’s new book Moral Imagination, which will be published by Princeton University Press in May. Copyright © 2014 David Bromwich.