There s lots of reasons for that shift The Labour Party choosing to step aside the Somme a changed international mood e g Versaille and the Fourteen Points IPP support for partition etc The conscription crisis really can not be forgotten about Sinn F in lost three by elections in 1918 before the conscription crisis Brian Feeney has the following to say about Representation of the People Act 1918 in Sinn F in a Hundred Turbulent Years In 1918 as a result of electoral reform all men over twenty one and women over thirty had the vote This provision almost trebled the electorate from 700 000 to just over 1 9 million It was this new electorate that gave Sinn F in its massive endorsement It is often overlooked that the IPP s candidates even in contests in the west and southwest actually sustained the party s vote quite well But the old party was simply not attractive to the new young voters mainly women and was swamped by them December 1918 was the real test of the IPP after decade of incredible change Twenty five constituencies may have been granted to Sinn F in unopposed but the 1918 election was also the first time since 1910 that 63 constituencies had been contested at all Also remember that Sinn F in didn t officially shift from monarchism to republicanism until 1917 In the mean time there was the formation of the UVF the Curragh Incident etc 1916 was one of a maelstrom of things that happened 10 years that has today s decade being rightly called a decade of centenaries