Daniel Sickles, the Congressman Who Murdered His Wife’s Secret Lover

Imagine Teresa Sickles, the wife of U.S. congressman Daniel Sickles, gazing out her window overlooking Lafayette Square in D.C. day after day for a year, anxiously awaiting the shake of a handkerchief that would signal another meeting with her lover.

At a young age, Teresa had been saddled with a much older husband who was not only a philanderer but someone who used his high-profile position to mask his degenerate behavior.

When Philip Barton Key, the well-regarded district attorney, widower father, and son of the author of “The Star-Spangled Banner,” began showing a romantic interest, it must have been a sweet relief from her life as Mrs. Daniel Sickles.

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But we will never know what Teresa was truly thinking. Like so many women of the time, her voice remains silent even though the fallout from the affair would ultimately be pinned on her in the court of public opinion. This despite the fact that, when the gunpowder settled, her notorious husband could now add “murderer” to his list of disreputable deeds.

On Feb. 27, 1859, Sickles spotted Key across the square from his home. He calmly put on an overcoat, loaded three pistols, and walked out the door. Within minutes, Key would be bleeding out on the ground having been shot point blank from each of the guns in broad daylight. Teresa was labeled a “wicked woman”; Sickles would be absolved in the press and the courtroom, where he launched the first successful insanity defense in U.S. legal history.

“Sir, you have dishonored me—prepare to die!”

By most accounts, Key and Teresa conducted their affair for over a year without the cuckolded husband being any the wiser.

Sickles was often out of town on diplomatic missions, ones he would frequently invite special lady friends to accompany him on. (It was well-known that some of those lady friends were prostitutes.) In a kind and welcome gesture, his friend Key would offer to escort Teresa to events around town while her husband was otherwise engaged.

What happened next surely followed the plot of love stories throughout time: a friendly elbow proffered turned into affection and then kindled into something more. Soon, Key and Teresa were making up excuses to see each other as often as possible. There were whispers, of course, but Sickles remained in the dark.

Until one day in February of 1859 when Sickles received an anonymous letter. The tattletale epistle not only disclosed the society gossip surrounding his wife, but it laid out in detail how the alleged affair was being conducted. The correspondent gave Sickles all the details he needed to catch the two in the proverbial act.

Almost immediately, Sickles tasked a friend with keeping watch over the house that Key had allegedly rented for his liaisons with Teresa. Soon, the friend spotted a man and woman who resembled the suspicious couple arriving at the home separately and entering through different doors. They stayed an hour, giving Sickles all the evidence he needed.

Sickles already had a tarnished reputation by the time he met Teresa. Though he first became acquainted with her family when she was only 3 years old, his romantic interest began a decade later. Fifteen-year-old Teresa was a gifted young woman from a prominent Italian family with music in their blood. (Her grandfather had worked closely with Mozart; her father was a famous singing coach.) She spoke five languages and by all accounts was smart and accomplished.

Sickles, on the other hand, was well-known for his debauched behavior. The lawyer-turned-politician had landed in professional trouble on several occasions for his flagrant womanizing and carousing. So when he asked Teresa’s family for her hand in marriage, it should have been no surprise that they said “no.” He married the 15-year-old anyway. Neither marriage nor his continued ascent up the political ladder did anything to stymie his exploits.

So one can imagine the shame and anger that Teresa must have felt when her hypocritical husband aggressively confronted her about her dalliance with Key on a late February day in 1859. He berated her until she confessed, and then forced her to put that confession into writing.

“I have been at the house with Mr. Key ... I did what is usual for a wicked woman to do ... an intimacy of an improper kind ... I undressed myself. Mr. Key undressed also ... [we] went to bed together,” the confession read according to the newspapers at the time, who received a leaked copy after it was ruled inadmissible in court.

But humiliating his wife wasn’t enough to soothe Sickles’s spurned soul. Around 2 p.m. on Feb. 27, the disgraced husband spotted his wife’s paramour in Lafayette Square and began the aforementioned preparations—coat, pistols, resolve.

Sickles approached the clueless Key, who said “How are you?” and stuck his hand out for a friendly shake. Contemporary reports recounted that Sickles dramatically responded, “Sir, you have dishonored me—prepare to die!”

Key reached a hand into his pocket, while Sickles withdrew one of the guns from his own, aimed, and shot. It was not a gun for which Key was reaching, but opera glasses, the same opera glasses he used to spy for signals from Sickles’ wife.

He attempted to toss them at the charging man, but the projectile specs were no match for Sickles’ firearms and anger. The latter pulled out another Derringer and shot Key a second time, at which point Key is reported to have shouted “Murder!” Sickles shot him one final time with his remaining pistol.

Key bled out within minutes while Sickles calmly returned home and then turned himself into the police.

Sickles, “not having the fear of God before his eyes, but being moved and seduced by the instigation of the devil,” as the indictment read, was charged with murder conducted “feloniously, wilfully [sic], and of his malice aforethought.” He pled not guilty.

Most of the newspapers of the day were firmly on the side of Sickles. Their reports raved about how good he was to his wife, how well provided for she was. “Mr. Sickles loved her with great devotion and lavished all his means upon her,” the Sunday Star wrote. The Boston Journal deemed the murder a case of “female infidelity” and described Teresa as “a much indulged and petted wife.”

It was perhaps this widely held public view—that a scorned husband had every right to take his revenge—that paved the way for the first successful insanity defense in the country’s history. Sickles had the backing of the president (Buchanan) and was represented by a seven-lawyer-strong defense team. Their opening statement lasted two days.

Sickles team pulled out all the stops, according to Alexis Coe in Lapham’s Quarterly. They quoted the Bible and Othello, characterized the crime as both a “justifiable homicide” and the result of a “temporary state of insanity.” Sickles put on a dramatic performance, at one point breaking down into sobs that so incapacitated him that a group of men had to carry him out of the room.

“We know that the Creator did not intend that homicide should be entirely excluded from the hand of man,” his lawyer James T. Brady argued in court. “None of us have forgotten the great command of our maker ‘Thou shall not kill’ any more than we have forgotten that other command ‘Thou shalt not commit adultery.’”

The prosecution countered by pointing out that the murder was clearly premeditated and not an act of mindless frenzy.

The jury deliberated for 30 minutes and declared Sickles not guilty for reasons of insanity. The court of public opinion applauded the decision and only turned against him when it became known that he would not be leaving his wife.

In the aftermath of the scandal, Sickles went on to have a long and distinguished career, though one that continued to be mired in dishonor and controversy. His leadership as a general during the Battle of Gettysburg was so terrible that nearly his entire unit was killed; he was fired by President Johnson from his role overseeing reconstruction in the Carolinas due to a poor performance.

It was discovered during his final act at the age of 93, when he was tasked with overseeing the construction of Civil War monuments in New York, that he had embezzled $23,000 from the commission that employed him.

But Sickles always seemed to come out on top. Just take the Civil War as an example: despite his horrific performance, he managed to earn a Medal of Honor for the sole fact that he lost a leg at Gettysburg. (He graciously donated his severed appendage to a medical museum, where varying accounts report everything from an annual pilgrimage to see the leg on his birthday to it being a frequent stop when Sickles had a new date he wanted to impress.) Despite a life mired in scandal, Sickles is buried at Arlington Cemetery.

But his biggest legacy is the insanity plea, which lives on in the U.S. legal system today. Though, as is only right given the theme of Sickles’ life, his own successful defense breaks down under scrutiny.

“Of course I intended to kill him. He deserved it,” he later admitted.

Given his remorselessness, one wonders if Sickles feared for his own life over three decades later when he served as the ambassador to Spain and began a torrid and not-so-secret affair with the country’s deposed queen. For his punishment, Sickles received a new nickname rather than three bullets—he became known as “the Yankee King of Spain.”