The Irish War of Independence was conducted under this revolutionary government which sought international recognition, and set about the process of state-building.

The IPP strove for Home Rule, that is, limited self-government for Ireland within the United Kingdom, and had been supported by most Irish people, especially the Catholic majority.

As the war prolonged and with the failure to make any progress on the issue, the more radical Sinn Féin began to grow in strength.

However, by 1918, under its new leader Éamon de Valera, Sinn Féin had come to favour achieving separation from Britain by means of an armed uprising if necessary and the establishment of an independent republic.

In the aftermath of the 1916 Easter Rising the party's ranks were swelled by participants and supporters of the rebellion as they were freed from British prisons and internment camps, and at its 1917 Ard Fheis (annual conference) de Valera was elected leader and the new, more radical policy adopted.

Prior to 1916, Sinn Féin had been a fringe movement having a limited cooperative alliance with William O'Brien's All-for-Ireland League and enjoyed little electoral success.

This was due to the failure to have the Home Rule Bill implemented when the IPP resisted the partition of Ireland demanded by Ulster Unionists in 1914, 1916 and 1917, but also popular antagonism towards the British authorities created by the execution of most of the leaders of the 1916 rebels and by their botched attempt to introduce Home Rule on the conclusion of the Irish Convention linked with military conscription in Ireland (see Conscription Crisis of 1918).

As a result, no election took place between 1910 and 1918, the longest gap in modern British and Irish constitutional history until then (it was superseded in Britain in 1935–45).

Forty-four outgoing members of the 30th Parliament did not seek re-election: Six MPs stood under a different political affiliation from the December 1910 general election.

Despite the isolated allegations of intimidation and electoral fraud on the part of both republicans and unionists, the election was seen as a landslide victory for Sinn Féin.

Four of their Ulster seats were part of the deal to avoid unionist victories which saved some for the party but may have cost it the support of Protestant voters elsewhere.

The IPP came close to winning other seats in County Louth and Wexford South, and in general their support held up better in the north and east of the island.

The party was represented in Westminster by seven MPs because T. P. O'Connor won the Liverpool Scotland seat he had held since the 1885 election due to Irish emigrant votes.

In Ulster (nine counties), Unionists won 23 out of the 38 seats with Sinn Féin gaining ten and the Irish Parliamentary Party five.

There was a limited electoral pact brokered by Roman Catholic Cardinal Michael Logue in December between Sinn Féin and the Nationalist IPP in eight seats.

The pact only broke down in Down East where a Unionist won as the IPP candidate refused to participate, thus splitting the Catholic nationalist vote.

There was no pact in Belfast Falls which Joe Devlin (IPP) won with 8,488 votes against 3,245 for Éamon de Valera (SF) although no Unionist stood.

The vote totals were:[8] On 21 January 1919, 27 (out of 101 elected) members representing thirty constituencies answered the roll of Dáil Éireann—the Irish for "Assembly of Ireland".

Dáil Éireann was, according to John Patrick McCarthy, the revolutionary government under which the Irish War of Independence was fought and which sought international recognition.

[1] Maryann Gialanella Valiulis says that having justified its existence, the Dáil provided itself with a theoretical framework and set about the process of state-building.

At its first meeting attended by 27 deputies (others were still imprisoned or impaired) on 21 January 1919 the Dáil issued a Declaration of Independence and proclaimed itself the parliament of a new state, the Irish Republic.

Although it had not ordered this incident, the course of events soon drove the Dáil to recognise the Volunteers as the army of the Irish Republic and the ambush as an act of war against Great Britain.

The train of events set in motion by the elections would eventually bring about the creation of the Irish Free State as a British dominion in 1922.

The leaders of the Sinn Féin candidates elected in 1918, such as de Valera, Michael Collins and W. T. Cosgrave, came to dominate Irish politics.

The two major parties in the Republic of Ireland today, Fianna Fáil and Fine Gael, are both descendants of Sinn Féin, which first enjoyed substantial electoral success in 1918.