Irish unionism was once nationalism.
It was always anti-democratic.
Their nationalism grew out of the pre-1800 Irish parliament. Their distaste for democracy came from the fact that the parliament represented the tiny population of Anglo-Irish landed gentry and clergy and excluded Catholics and Presbyterians. As calls for Catholic emancipation grew alongside Presbyterian radicalism the gentry saw the dissolution of the parliament and the Act of Union as preserving ascendancy by diluting Catholicism in a wider British context.
So, the main reason for the act of union was the emergence of a genuine democratic alliance of Catholics and Dissenters. Inspired by the French revolution, the 1798 rising of the United Irishmen was a real threat to British rule. The revolution had been defeated following a British military mobilisation. The Presbyterians were a minority in the North and met savage repression. A section of the southern movement, led by reactionary Catholic clerics, indulged in sectarianism and helped divide the democratic movement.
The United Irishmen live on in Republican mythology as representing the possibility of unity around the national question, but their defeat saw that possibility recede. In part this was due to the especially heavy repression of the Presbyterians. A common punishment was the pitch cap, boiling pitch poured over the heads of the victims. Many who were spared that fate were transported to Australia. Militancy faded with a local industrial revolution. The linen trade was excluded from the general suppression of Irish industry and led to economic growth. New opportunities opened for Presbyterians as mediators between the aristocracy and industrialists and a new influx of Catholic workers. In the South the burning question became Catholic emancipation, with an Irish Party led by moderate parliamentarians. The republican component, the Irish Republican Brotherhood, became organised in the Irish Diaspora, especially in the US, and turned towards conspiracy and militarism.
The next revolutionary opportunity would include a growing working-class movement. It was a minority but was at the forefront of emerging class struggles and was also a doorway to a massive international movement. However, that movement was fragmented. Most industrial growth was in the North, led by the British imperial market and local unionist industrialists. This led to Walkerism, a "gas and water" municipal socialism denounced by James Connolly. Also, within Ireland, Britain, and the wider international labour movement there was a sharp division between revolutionary and reformist currents.
In 1913 the Irish revolutionary workers current faced a major setback. The great Dublin lockout for union recognition had ended in a qualified defeat, with the workers forced back to work. Having successfully resisted the unions, the intensity of the struggle saw the employers gradually give way to union organisation, but it also convinced a large section of the union and labour movement, especially in the British headquarters, of the dangers of radicalism. It was in response to labour conservativism that Connolly moved between unions, socialist parties and the Irish Citizen Army. He was by far the most charismatic and articulate of working-class leaders in Ireland, but he was also in a minority.
Setbacks for the workers and a growing tide towards imperialist war (ironically proclaimed as being in defence of the freedom of small nations) shifted the balance of forces towards the revolutionary nationalists, organised in the Irish Republican Brotherhood (IRB).
There is a tendency to run together the revolutionary nationalists and the workers as "men (sic) of no property". It would be better to call the IRB "men of little property" concentrated in the middle classes.
This had a number of consequences. Many nationalist radicals strongly sympathised with the workers, but they saw the nation, not class, as the central focus of struggle. “Labour must wait”, became a slogan. Methods of conspiracy and militarism moved centre stage. Above all an enduring concept of the nationalist family, still a major force today, made the republicans largely blind to class differences with the nationalist bourgeoisie.
For Connolly the 1916 rising did not hold out the prospect of a military victory. Alongside his support for Irish self-determination ran a desire to strike out alongside the revolutionary elements associated with the second international in opposition to imperialist war. In the aftermath of 1916, the reformists criticised him for supporting the rising, while Lenin and Trotsky believed he had risen too soon.
The Irish Republican Brotherhood did dream of victory, but this involved a complicated conspiracy. They were hidden inside the nationalist Irish Volunteers and hoped to convert a mobilisation into a rebellion. The more moderate majority leadership countermanded the mobilisation and the rising became an act of defiance rather than a realistic attempt to take power.
Irish capitalism was riven with division. The Irish Volunteers were formed as a defensive response to the Ulster Volunteer Force and did not foresee rebellion. The political leadership was the Irish Parliamentary Party, committed to Home Rule via parliamentary action. Their leader, John Redmond, accepted the postponement of Home Rule because of the war and then supported mass enlistment into the British army in down payment of future good behaviour by the British.
British savagery after 1916, the execution of the leadership and the naval bombardment of Dublin, blew the old order apart.
The old nationalist party collapsed and a new Irish resistance cohered around Sinn Fein, until then a minor force. The mass political support led the majority of those elected in 1918 to convene the first Dáil and to organise both Dáil and local councils to run Ireland as an independent country. Parallel to the political movement ran a military organisation, the IRA, waging a guerrilla war against British forces. The republican imagination sees the IRA as the decisive transformative force on the war of independence. In reality the alternative state set up by the resistance was far more important. Military action was important also but, in the countryside, its main role was to disperse the concentration of British forces. In the cities, along with the civilian population, it managed to break much of the intelligence apparatus the British depended on. The militarist focus allowed much of the manoeuvring of constitutional nationalism to take place in the shadows
What happened to the Irish Party and to the capitalist interests it represented? Many joined Sinn Fein. The Nationalist divisions did not go away. They were subsumed in one movement.
When the British offered a settlement of limited Home Rule and partition the hidden fractures re-emerged as pro and anti-treaty forces.
The divisions led to violence and the British immediately provided the pro treaty forces with field guns. A savage civil war filled with reprisal, torture, and massacre led to the defeat of the Republicans.
The result was a confessional state in the South. The hospitals, social services and the schools were left to the tender mercies of the church. A ruling class determined to protect existing property relationships and cut off from the industrialised North could not bring about a truly independent economy. Ireland exported its people. The poor fled in search of work. The rebels and intellectuals fled the stranglehold of the church.
Republican revolutionaries never came to terms with the role of constitutional nationalism. They ignored the constant repression by Fianna Fáil and launched a doomed border campaign; "Operation Harvest'' that was repressed on both sides of the border. Even when Provisional Sinn Fein emerged as the leadership of a mass movement in the 70s the eventual outcome was capitulation to the interests of Irish capitalism. If the national question was the only dominant question, then by definition the capitalists were part of the nationalist family. A class policy, based on all the issues facing the workers, was the only ground on which revolutionary independence could have been found.