Click on the photographs of William Perkins Black (Windneath Photographers) and Leonard Swett (C. D. Mosher) to read printed versions of their respective oral arguments before the Illinois State Supreme Court. Black's argument is approximately 13,800 words, and Swett's is approximately 3,900 words.

The appeals process before the Illinois Supreme Court required the lawyers for both sides to submit written briefs and oral arguments (see the "Defending the Verdict" entry in the "Higher Laws" section of this Act). They presented their oral arguments to the justices from March 13 to 15, 1887.

Black told the court that all his clients wanted was justice. He argued that they had been convicted by a biased judge and an improperly constituted jury. Finding them guilty of murder because they were somehow part of a "conspiracy" that may or may not have included the "unknown party" who threw the bomb made no legal sense. "Our point is this," Black explained: "There can be no finding justified in the law that this bomb was thrown by a member of that conspiracy, or through the procurement of a member of that conspiracy, without evidence showing fairly, and such as to justify the conclusion of the jury based upon it, that THE MAN who threw that bomb had been by the accused advised, aided, or encouraged to that act." The verdict reflected an uncivilized desire for revenge, not justice. It marked a revival of the barbaric lex talionis, or law of retaliation—seven police officers had died, and now seven anarchists were being forced to pay with their lives.

Much of the conduct of the trial from the indictment onward was unfair and irregular, Black further maintained, and a good portion of the state's evidence was illegitimate and its testimony incorrect. Gary's rulings on defense objections and motions were consistently prejudicial and wrong. Black then offered a long list of errors in impaneling and instructing the jury, as well as complaints about several of Gary's and Grinnell's remarks in court.

In his argument, Swett reiterated many of these points in a tone both more pointed and more eloquent. The prosecution had not proved that his clients were directly or indirectly guilty of the bombing. They might be fairly accused of "intemperance, extravagance and foolishness of speech," but "under the laws of Illinois a person cannot be hung for foolishness of oratory or writing foolish newspaper articles; nor can one person be hung for the act of another."

As for the fact that Lingg made dynamite bombs, Swett said that in his opinion this act ought to be criminal, but he added immediately that under current Illinois law it was not. In any case, both he and Black asserted, the problems with the trial went far beyond legal technicalities to the fundamental issues of fair and rational judgment based on fact. These men were "tried in times and under circumstances of great unpopular excitement," which explained why "much irrelevant and unlawful evidence was introduced against them," a mistake the justices now had the opportunity to amend. If the state executed the anarchists simply for advocating revolution, Swett reasoned, then many ardent Republicans who spoke out uncompromisingly against slavery could have been hanged along with abolitionist John Brown for his bloody assault on the federal arsenal at Harpers Ferry in 1859.

"Respectable" citizens like Swett, who, three decades earlier, had been ardent anti-slavery advocates, frequently cited this last point outside the court. In his own argument, State's Attorney Grinnell did not entirely refute the parallel, but instead stated that Brown was far less dangerous a figure than the anarchists. His chances of success were "infinitely less" than theirs were, he had no weapons comparable to dynamite, his ring of "conspirators" was tiny, and his anticipated support from "ignorant and cowardly" slaves was entirely unrealistic.

Swett (1825-1889) was a native of Maine who had been a resident of Illinois since 1848 and of Chicago since 1865, where he became one of the most admired lawyers in the city. He had been a law associate of Abraham Lincoln, whom he served as an adviser after the latter's election to the presidency, as well as a founder of the Republican Party, and an outspoken opponent of slavery.