A priest, a president, and one slander suit
Charles Chiniquy was a Canadian-born Catholic priest who became a celebrated temperance preacher, quarrelled with his bishop, left the Church, and spent the rest of a long life writing against it. He died in 1899. From 1885 he argued in print that the Society of Jesus had arranged the murder of Abraham Lincoln, and that John Wilkes Booth had been its instrument.
He did not put it cautiously. "Booth was nothing but the tool of the Jesuits," he wrote. "It was Rome who directed his arm, after corrupting his heart and damning his soul."
The argument ran to more than sixty pages of his autobiography Fifty Years in the Church of Rome, and his posthumous editors gave it twenty more in a second volume. It was later reissued on its own as The Murder of Abraham Lincoln Planned and Executed by Jesuit Priests. The whole of it rests on a single foundation: that Chiniquy and Lincoln had been close, and that the closeness began when Lincoln defended him against the Church in an Illinois courtroom in 1856.
What happened in 1856
There was a case. A Kankakee layman named Peter Spink sued Chiniquy for slander after Chiniquy accused him of perjury. The suit moved from Kankakee County to Champaign County, was tried there in May 1856, and ended in a hung jury. It was set to be retried at Urbana that October. Lincoln, riding the circuit, acted for Chiniquy.
A letter Lincoln wrote to Abraham Jonas on 21 October 1856 places him at the case during that autumn's campaign season, and the University of Illinois holds his legal papers from it. What those papers describe is not a trial. Lincoln settled the matter before it reached a jury: Chiniquy apologised, paid his share of the costs and Lincoln's entire fee, and Spink agreed to drop the suit. The case was dismissed.
Chiniquy's account has Lincoln winning a courtroom victory over Bishop Anthony O'Regan, who had, in his telling, hired Spink to destroy him. Paul Laverdure, who went through the court records and newspaper accounts for the Canadian Society of Church History in 2001, put the difference plainly: "There had been no Lincoln victory over a Catholic bishop. There had been no bishop, no victory, and probably very little contact between Lincoln and Chiniquy."
The friendship the theory needs is similarly thin on the page. Chiniquy described private meetings at the White House in which Lincoln confided his fear of Rome. Marcel Trudel, Chiniquy's biographer, noted that nowhere in the collected editions of Lincoln's writings is there "the smallest bit of paper" mentioning such a visitor. Carl Sandburg's four-volume life mentions Chiniquy exactly once, in connection with the Urbana case; the 1954 abridgement dropped him.
Chiniquy anticipated the objection and answered it in advance. Lincoln had concealed the conversations, he wrote, because "if the people knew the whole truth, this war would turn into a religious war, and it would, at once, take a tenfold more savage and bloody character."
The order the argument was built in
The sequence in which Chiniquy assembled his case is recoverable from the case itself, and it runs backwards from the usual direction.
The declaration that Booth was a Jesuit tool appears at the opening of his account, before any evidence is offered. The sentence that follows it describes how he came to write: "After I had mixed my tears with those of the grand country of my adoption, I fell on my knees and asked my God to grant me to show to the world what I knew to be the truth, viz.: that that horrible crime was the work of Popery." The affidavits he relied on were gathered in 1883, eighteen years after the assassination and after that prayer.
Laverdure reduced the reasoning to its skeleton. Catholics were among those charged as conspirators; therefore, in Chiniquy's handling, conspirators are Catholic; therefore Booth, a conspirator, was a Catholic; therefore Mary Surratt, a Catholic, was a conspirator. Each step is presented as a finding. None of them is a fact about Booth.
What the conspirators were
The part of the theory that has kept it alive is that it is not built on nothing. Two of the people around Booth had genuine Catholic histories, and one of them ended up in the service of the Pope.
John Surratt, son of the boarding-house keeper Mary Surratt, had studied for the priesthood at St. Charles College alongside Louis Weichmann; both left the seminary in 1862 without being ordained. After the assassination Surratt fled to Canada, was sheltered by a priest, sailed for Britain under a false name, reached Rome, and in December 1865 enlisted in the Papal Zouaves as "John Watson." He was recognised, arrested, escaped, was recaptured in Egypt and returned to the United States, where his trial ended in a hung jury.
That is a strange sequence of events and it is entirely documented. It is also the whole of the Catholic connection. Of the people tried for the conspiracy, most were Protestant where they had any affiliation at all. Booth's own religion was vague; what the record of his life shows is a man moved by Southern sentiment and by his own sense of consequence. No document produced in 1865, or since, places the Society of Jesus anywhere near the planning of the murder, and the affidavits Chiniquy collected in 1883 do not name a Jesuit who did anything.
Why it lasted
The theory did not survive on its evidence. It survived because it was useful.
Chiniquy wrote for a nineteenth-century Protestant readership in the United States and Canada that already believed the Catholic Church to be hostile to republican government, and he gave that belief a martyr. His books sold heavily and stayed in print. Canada later classified some of his work as hate literature and barred its import.
Historians dealt with it early and then mostly stopped. Joseph George examined the Lincoln writings for the Journal of the Illinois State Historical Society in 1976; William Hanchett gave the assassination theories a full accounting in The Lincoln Murder Conspiracies in 1983. Both concluded there was nothing in it, and the professional literature moved on to arguments it found more interesting, chiefly Otto Eisenschiml's case against Secretary of War Edwin Stanton.
It has not stopped circulating. Laverdure recorded in 2001 that a film company had approached him wanting historical support for a documentary proposal arguing that the Catholic Church had been involved in every presidential assassination. He looked at the records and declined, which is roughly what everyone who has looked at the records has done.
What remains is a real court case, a real settlement, a real seminarian in a papal uniform, and a conclusion written down before the evidence for it was collected.