Facing multiple indictments for treason as a result of his role in fomenting the 1798 rebellion, he effected a number of daring escapes but was ultimately forced by his government pursuers into exile in France.

He worked to assist Robert Emmett in coordinating a new rising in Ireland in 1803, and later had contact with the Spencean circle in London implicated in both the Spa Field riots and the Cato Street Conspiracy.

[4] His father was renowned for having rallied members of the church and others in town in 1786 to oppose and defeat a proposal by the wealthy merchants and West-Indian slaveholders Waddell Cunningham and Thomas Greg to commission vessels in the port for the Middle Passage.

[7] Shortly after his father's business premises in Belfast had been ransacked by soldiers in February 1793, the young McCabe returned from a textile apprenticeship in Manchester, in his own words "imbued, not merely with the political, but, unfortunately also, with the religious opinions, of Paine".

Thomas Russell recorded an interview with McCabe and Neilson in April 1793 from which he understood that the people in the north were "burning with indignation" against the government (the British-Crown appointed executive in Dublin) and that they "have gone to the greatest lengths to hold out their hands [to] the nation [the Protestant Ascendancy who were alone represented in the Irish Parliament] to join them in reform but they have refused".

Among other roles, he assumed that of an itinerant preacher (changing halfway through his sermon to a discourse on the politics of the day), a mendicant, a farmer, a pedlar, and a British army recruiter (under which guise he persuaded a judge in Roscommon to release Richard Dry and other Catholic Defenders to his custody).

[13] That Kelly and Cloney were sworn United Irishmen in advance of the rebellion, however, has been disputed, and in general, there appears to be conflicting evidence of the level of organisation that McCabe actually achieved.

He then appeared among rebels in Kildare (where a government spy reports McCabe confessing to having seen action), and, in September, with French General Humbert's small landing force in Mayo.

[16] Before departing for the Continent McCabe travelled to Scotland, where he made contact with the United Irish leaders imprisoned in Fort George and among whom he seems to have won the confidence of Thomas Russell and William Dowdall.

[17] For the new United Irish Directory in exile he undertook a number of missions, with reports of his presence in London, Manchester, Nottingham, Stockport, Glasgow, Paisley, Belfast and Dublin.

[22] Among the exiles in Paris, Arthur O’Connor, following his marriage in 1807 to the daughter of the Marquis de Condorcet, borrowed money from McCabe to acquire a country residence.

Emmet was their unwitting instrument, drawn home from Paris for the purpose of organising a rising by McCabe's misrepresentations of conditions in Ireland and with O'Connor's encouragement.

[19] In 1814 there are French police reports of several members of this Spencean circle involved in these incidents contacting Irish emigres in Paris, including McCabe (alias "Cato").