Abraham Carlisle and John Roberts Trials: 1778

As early as mid-July this resentment took political form. Citizens' organizations were formed in Philadelphia to gather evidence against collaborators with the British during the occupation and bring them to justice. In addition, there were threats of extralegal activity, physical attacks, and harassment against persons accused of having supplied the British with information or goods, or having cooperated with them in any way. Newspapers printed the names of suspects.

Thomas McKean, chief justice of the Pennsylvania Supreme Court, anxious to avoid the possibility of vigilante justice against collaborators, set the court system in motion as quickly as possible to handle their cases. Through August and September, he and his two fellow justices sat in the city hall collecting evidence and interviewing accused persons. McKean, who believed that moderation toward dissidents was good policy in wartime, released all the accused on bond, commenting that no credible evidence had yet been produced against them. The Philadelphia grand jury, however, after hearing the evidence, brought in 33 indictments for the September court, most of them for treason—collaboration with the enemy—which was punishable by death under state law.

Abraham Carlisle was one of the first defendants brought to trial. A prosperous, elderly carpenter, he had guarded the city gates under the British rule, and was therefore charged with having accepted a commission from them. Several witnesses testified to his service as a guard, but his defense lawyers argued that he could not be convicted of treason, since no written commission was produced. The jury deliberated 24 hours and found him guilty. His conviction was appealed to the Pennsylvania Supreme Court and was upheld. The State Executive Council, which had the power to commute Carlisle's sentence, turned down numerous appeals to do so, including one from Justice McKean, who had originally pronounced it.

A few days after Carlisle's conviction, and after several other defendants had been acquitted of charges of treason, the case of John Roberts came up. Roberts, like Carlisle, was a prosperous older citizen, in this case a miller. He was charged with recruiting men to join the British army. Testimony showed that he had in fact attempted to persuade men to enlist in the British forces, but his defense lawyers argued that his efforts were unsuccessful and that he could not be convicted unless the prosecution showed that someone had actually enlisted as a result of Roberts's persuasion. They also objected to the introduction of his confession, which could not, they said, be used as evidence in a trial for treason. These arguments failed to convince the jury, which found Roberts guilty as charged. His case, like Carlisle's, was appealed to the Supreme Court and the State Executive Council, and the sentence affirmed by both authorities. Carlisle and Roberts were hanged on November 4, 1778.