In 1911 a Parliament Act was passed that limited the power of the Lords' veto to temporary obstruction, allowing the Liberal government under Herbert Henry Asquith, dependent on the support of the Irish Parliamentary Party, to introduce a third Home Rule Bill in 1912. 

The bill was met with fierce opposition from Unionists in Ulster, almost half a million of whom in 1913 signed a Solemn League and Covenant to resist it. Around this time the possibility of a temporary or permanent exclusion of Ulster from its jurisdiction began to be debated. 

The Unionist leader Edward Carson made preparations to set up a separate provisional government in Ulster, and the Ulster Volunteer Force, a militia organised in 1913 and armed with rifles imported from Germany, was mobilised to enforce such an action. In response, Nationalists formed the Irish Volunteers to defend Home Rule. 

In May 1914, on the eve of World War I, the bill was passed into law. It was decided, however, with Nationalist and Unionist agreement, to suspend the operation of the Home Rule Act until after the war. 

Soon after the outbreak of war, the Irish Volunteers were split after Redmond persuaded the majority to enlist in the British Army, in the hope of securing future political concessions from the government. The remaining Volunteers, a small minority of between perhaps 2,000 and 3,000 members, together with the trade-unionist Irish Citizen Army, were directed by the IRB (Irish Republican Brotherhood) in the Easter Rising that took place in Dublin in 1916. The rising, severely hampered by uncoordinated leadership and the interception of weapons smuggled by Roger Casement from Germany, lasted five days and caused over 200 civilian deaths and enormous destruction of property. 

Although it was unpopular at the time, the execution of 15 of its leaders, including Patrick Pearse and Sean MacDermott, afterwards engendered widespread sympathy and evoked strong nationalist feeling throughout the country. In the general election of November 1918 Sinn Féin, although it had not been directly involved, was popularly associated with the rising and largely as a result won 73 out of 80 nationalist seats, effectively marking the demise of Redmond's Parliamentary Party.