Drennan had been active in the Irish Volunteer movement and achieved renown with addresses to the public as his "fellow slaves" and to the British Viceroy urging "full and final" Catholic emancipation.

Through his father's mentor, the Irish moral philosopher Francis Hutcheson (1694-1746), a new generation of Scottish thinkers had drawn on the republican ethos of Presbyterian resistance to royal and episcopal imposition to defend what Drennan called "the restless power of reason".

[6] Sharing the sympathies of many Ulster Presbyterians (few without kindred in the colonies), Drennan greeted news of Britain's first defeat in the American War of independence (Burgoyne's surrender at Saratoga in 1777) as cause to "congratulate the people of Belfast and all mankind".

If the Irish parliament remained an almost exclusively an Anglican (Church of Ireland) assembly in the pocket of the Kingdom's largest landowners it was because no counterweight could be found in the absence of the great body of the nation that the English-dependant "feudality"[9] had dispossessed.

Now was the time for patriot Churchmen and Presbyterians to display "zeal in politics and moderation in religion" and as Irishmen, "nurtured by the same maternal earth", to join with Catholics in a "sacred compact".

[11]In June, Drennan circulated in Dublin, and forwarded to McTier in Belfast a further document, outlining in greater detail the same proposition: an "Irish Brotherhood" that would overcome "the distinctions of rank, of property, and of religious persuasion" through a programme of public education and correspondence with like-minded societies in throughout Ireland, Britain and France.

[12] At its first meeting in Belfast in October 1791, the "conspiracy", calling itself at the suggestion of Theobald Wolfe Tone, the Society of the United Irishmen, resolved on the complete emancipation of Catholics and an "equal representation of all the people" in parliament.

[13] Employing, as Drennan had proposed "much of the secrecy and somewhat of the ceremonial of Free-Masonry",[14] the Society spread rapidly across the Presbyterian districts of the north, to Dublin and, in alliance with the Catholic Defenders, across the Irish midlands.

At the first meeting of the Society in Dublin in November 1791 Drennan won unanimous consent for his draft of a solemn declaration or test to be entered into by every member.I, - AB in the presence of God, do pledge myself to my country, that I will use all my abilities and influence in the attainment of an impartial and adequate representation of the Irish nation in parliament: and as a means of absolute and immediate necessity in accomplishing this chief good of Ireland, I shall do whatever lies in my power to forward a brotherhood of affection, an identity of interests, a communion of rights, and a union of power among Irishmen of every religious persuasion, without which every reform must be partial, not national, inadequate to the wants, delusive to the wishes, and insufficient for the freedom and happiness of this country.

The "circumstances of the times as well as the persons" had changed "in the very manner wished for": "to commercial interest, a middle and a mediating rank had rapidly grown up in the Catholic community" producing an "enlargement of mind", "energy of character" and "self dependence".

Following his successful defence at trial by John Philpot Curran in June 1794, and as the leadership began to seriously consider prospects for an insurrection, Drennan appears to have dropped out of the inner counsels of the United Irishmen.

To his sister Martha McTier Drennan wrote: "Is it not curious... that I, who was one of the patriarchs of the popular societies, should... be excluded and treated as a frigid neutralist, until I... throw myself, as other patriot suicides, into the gulf of a prison".

[21] It may be a testament to his sister's influence that when William Bruce protested that an "impartial" representation of the Irish nation implied that not only Catholics but also "every woman, in short every rational being shall have equal weight in electing representatives",[16] Drennan did not care to disabuse him.

With the enemies of the Revolution triumphant under the Duke of Brunswick at Verdun, it was "no time to weigh nice points of morality"--"if a boat escapes from a wreck be sinking with the weight of men, some of them ought to be thrown to the sea".

[26] When January 1793 Louis XVI, as citizen Capet, was guillotined, Drennan regarded it as "necessary to save the French Republic", although certain to serve Britain by making war with France popular.

[31] Convinced that the object of many of the Catholic members was "selfish" (i.e. focused on emancipation rather than constitutional reform), with Thomas Addis Emmet, Drennan had promoted a secret "inner Society" in Dublin (the McTiers in Belfast were to tell no one) which was "Protestant but National".

[35] Drennan's creation within the Dublin Society of a "private junto"[36] has been suggested as one of the reasons for the willingness of the Catholic printer William Paulet Carey—a committed democrat equally suspicious of the Committee Catholics—to testify (truthfully) in May 1794 to the physician's authorship of the Volunteer address.

[40] Conscious as he was that opinion among the United Irish and Defenders was running in the direction of a French-assisted insurrection, Drennan nonetheless tasks the Lord Lieutenant with averting a "rude and revolutionary collision".

He directs Fitzwilliam's immediate attention to reform: "full and final" Catholic Emancipation, the promotion of manufactures to provide employment for the landless, and a system of "universal education" that can "assimilate all religions".

[43] Consistent with "the fundamental article of the British Constitution that holds taxation to be "inseparable" from representation", where people are denied legislative power they have "the same reason to complain as the Americans had lately, on the other side of the Atlantic, or as the Catholics had at our doors".

[45] When United Irish leadership still at liberty sought to muster their members in arms in May and June 1798, Drennan continued in Dublin, the heavily garrisoned capital in which no rebel demonstration proved possible.

[24] In January 1799 Drennan published an open letter to the British Prime Minister William Pitt assailing his proposals to abolish the Kingdom of Ireland and to incorporate the country with England under the Crown at Westminster.

With his own sister, Martha, Drennan shared disgust at the subscription made by Dr. James MacDonnell in Belfast to the reward for the capture of Emmet's confederate, their mutual friend Thomas Russell.

In a poem sketched for Martha, Epigraph-on the Living (October 1803), Drennan decries "a man who could subscribe To hang that friend at Last Whom future history will describe The Brutus of Belfast.

[55] His suspicions appeared confirmed when, in 1816, it was reported that at a St. Patrick's Day dinner board members and staff had raised a succession radical toasts to Drennan for his services to the cause of Catholic Emancipation and Parliamentary reform, to the French and South American Revolutions, and to "The exiles of Erin" under "the wing of the republican eagle" in the United States.

Despite the resignations of the board members present (Drennan at the time was in England), including Robert Tennent the presiding chairman, it was several years before the government was persuaded to restore its grant of £1,500.

[60] It attacked absentee landlords who "riot in the wantonness of luxury" while leaving management of their estates to an agent, "whose principle business is to ingratiate himself with his master, by squeezing the uttermost farthing of rack-rent out of the starved bellies of a laborious and industrious tenantry".

In campaigning to remove the remaining sacramental barriers to their participation in Parliament and the higher offices of state, Catholics might help restore a sense of public spirit to Irish society, but not if they determined to do so exclusively by their own efforts.

In autobiographical verses written in 1806, Drennan presents the failure to attain Irish independence as a measure of a life unfulfilled:[68]Still shrinking from praise, tho' in search of a name He trod on the brink of precipitate fame;And stretch'd forth his arm to the beckoning form,A vision of glory, which flashed through the storm,INDEPENDENCE shot past him in letter of light,Then the scroll seemed to shrivel and vanish in the night;And all the illumin'd horizon became,In the shift of a moment a darkness--a dreamLater, he appeared to relent.

His headstone inscription reads:[74] Pure, just, benign: thus filial love would trace The virtues hallowing this narrow space The Emerald Isle may grant a wider claim And link the Patriot with his Country's name With Sarah Swanwick, Drennan had one surviving daughter and four sons.