An illustration of the slaying of Philip Barton Key II in Harper’s Weekly. (Library of Congress)

The affair began, Teresa Sickles remembered, in the spring of 1858.

She was the 23-year-old wife of first-term New York Democratic congressman Daniel Edgar Sickles. Her lover, Philip Barton Key II, was the district attorney for Washington and the son of Francis Scott Key, who wrote the lyrics of “The Star-Spangled Banner.”

The couple would rendezvous not far from the Sickles home on Lafayette Square, where they lived just steps from the White House, at an unoccupied house on 15th Street. There, as Teresa put it in a written confession demanded by her husband after he learned of the affair, they engaged in “intimacy of an improper kind.”

More colorfully, she put it another way: “I did what is usual for a wicked woman to do.”


Teresa Sickles as seen in Harper’s Weekly. (Library of Congress)

Then, as now, extramarital dalliance was not uncommon among the men and women who moved in the capital’s social and political circles. Rep. David Outlaw, a North Carolina Whig who served in Congress during the late 1840s and early 1850s, filled letters to his wife with details of “congressmen going home with married ladies, women sending married men valentines, and even a senator producing a child out of wedlock with a boardinghouse owner,” historian Rachel A. Shelden has written.

Outlaw discreetly declined to share this gossip with the press, Shelden notes. But the affair between Sickles and Key took a violent turn on Feb. 27, 1859, that made it national news.

Outwardly, the Sickleses — who married when she was 16 and he was 33 — seemed like many of the ambitious power couples that turn up in Washington. They were the parents of a 6-year-old daughter. They held receptions, dinners and balls at their home on what is now Jackson Place on the west side of Lafayette Square.

The sociable new congressman — later a Union general who would lose a leg at Gettysburg — bonded with Key over an all-night game of whist in March 1857, as James Buchanan took office, according to author Nat Brandt.


Rep. Daniel Sickles (D-N.Y.) in Harper’s Weekly. (Library of Congress)

“In some ways, the two men were alike — both debonair, ingratiating, wise to the way of politics, egocentric and rebellious, arrogant and quick to take affront, yet sociable,” Brandt writes in “The Congressman Who Got Away with Murder.” “Both were dissemblers — Barton, for one thing, about his health, Dan about politics and religion. And both were womanizers.”

Key also became acquainted with Teresa — and the capital’s “polite society” took notice, according to Harper’s Weekly. “They were always together,” the magazine reported. “At balls, at parties, in the street, at receptions, at theatres, every where, Mrs. Sickles was invariably accompanied by Phil Barton Key, District Attorney.”

Eventually they became lovers, but Daniel Sickles was apparently oblivious. That changed the evening of Feb. 24, 1859.


Philip Barton Key. (Library of Congress)

Daniel and Teresa had entertained dinner guests that evening. Most of the party headed to a dance at the Willard hotel when the congressman received an anonymous letter that he stuffed, unopened, in his pocket. When he returned from the Willard, Harper’s reported, he opened the letter and learned of the affair.

Key “hangs a string out of the window” of the house on Fifteenth Street “as a signal to her, and leaves the door unfastened,” the letter, reproduced in Harper’s, read. “With these few hints, I leave the rest for you to imagine.”

Apoplectic, Sickles confronted his wife, who quickly admitted to the liaison. He demanded that she make a confession in writing — and waited to take his revenge on Key.

The opportunity presented itself two days later. Sickles spied the district attorney walking along Madison Place on Lafayette Square, signaling for Teresa. The lawmaker — armed, the New York Tribune reported, with two single-barrel Derringers and a revolver — stormed out of his house toward Key on the other side of the park.

Key extended his hand, thinking the encounter would be friendly. He quickly found out otherwise.

“You have dishonored my home and family,” Sickles roared, the Washington Evening Star reported. Each reached inside their jackets — Key for a pair of opera glasses to hurl at the advancing lawmaker, and Sickles for a Derringer. Sickles began firing. Key staggered, but continued to advance at his adversary. Sickles fired again, and Key fell to one knee. After a third shot from the congressman, Key fell to the ground, dead. Sickles then walked to the house of a neighbor, Attorney General Jeremiah S. Black, and surrendered.

Washington — and the rest of the country — was aghast.

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“The tragic affair produced a great sensation,” the New York Herald reported. “In the streets, the law courts, public houses, private dwellings, and, in fact, everywhere, it was the prominent topic of conversation.”

The case seemed straightforward. Sickles admitted shooting Key and expressed no remorse for killing the district attorney who had cuckolded him.

“He has dishonored me, and we could not live together on the same planet,” Sickles told the New York Tribune in a jailhouse interview.

But Sickles had no intention of pleading guilty and passively accepting the judgment of the court. He assembled a top-flight defense team that included lawyers from New York and Edwin M. Stanton, a well-connected attorney in Washington who would in later years serve in the Lincoln administration as secretary of war and become a leading Radical Republican.

At the time, Stanton moved in Washington’s Democratic circles, and his relationship to the president and the congressman suggests that Buchanan may have asked him to join the defense team, according to Brandt.


The scene at the Sickles trial, as rendered in Harper’s Weekly. (Library of Congress)

Sickles’s defense featured an unusual argument. In addition to presenting their client as a wronged man, attorneys argued that he was temporarily insane at the time of the shooting. Insanity had long been a staple defense argument. “But no one had ever raised the notion of someone being only temporarily mad,” Brandt notes.

(Temporary insanity continues to be used by defense attorneys and was successfully employed by Lorena Bobbitt, who was found not guilty by reason of insanity in Manassas, Va., in 1994, after being charged with cutting off her husband’s penis.)

The Sickles defense did not rely entirely on legal novelties. Although the confession was not admitted into evidence, the reputation of Teresa Sickles became collateral damage as the lengthy affair was documented in detail. Brandt describes how Stanton told the court that her affair with Key had put her on the road toward “the horrid filth that is common prostitution.” The courtroom erupted in applause as Stanton described Sickles’s motives as honorable — “the death of Key was a cheap sacrifice to save one mother from the horrible fate,” the attorney declared.

The two-pronged defense strategy — portraying Sickles both as briefly unhinged and acting with justification — proved effective. The presiding judge bought the argument about temporary insanity and instructed the jury to consider Sickles’s state of mind at the time of the shooting, Brandt writes.


The New York Herald, April 27, 1859.

“The trial was a fiasco,” according to Shelden. The jury deliberated for a little more than an hour before returning a not-guilty verdict. “[C]heer after cheer resounded in the Court room,” the Herald reported, “and it was taken up by the multitude outside and repeated.” Others were appalled.

“We regard this as a most mistaken and most mischievous verdict — a sanction to the substitution of violence and vengeance for reliance on the regular and orderly redress of grievances through the instrumentality of law,” the Tribune editorialized. “It is a verdict which carries this country a long stride backward toward the age when Might was Right, and all wrongs were redressed by the red hand, or not at all.”

The sensational series of events produced one more shock. After the trial, reports surfaced that Daniel and Teresa Sickles had reconciled. The congressman confirmed their rapprochement in a letter to the New York Herald on July 19 in which he pleaded for the public to leave Teresa alone and direct its fury at him.

The reconciliation appalled the Victorian moralists who had justified Sickles’s actions. “We hope the sympathizers with Mr. Sickles at Washington, and especially the jury who exalted him into a great champion of the sanctity of marital relations will be satisfied with this result,” the Baltimore American sneered.

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