In the 1918 general election, Sinn Féin won 73 out of the 105 Irish seats in the House of Commons. Elections were held almost entirely under the 'first-past-the-post voting' system. In 25 constituencies, Sinn Féin won the seats unopposed. Unionists (including Ulster Unionist Labour Association) won 26 seats, all but three of which were in the six counties that today form Northern Ireland, and the IPP won only six (down from 84), all but one in Ulster. The Labour Party did not stand in the election, allowing the electorate to decide between home rule or a republic by having a clear choice between the two nationalist parties. The IPP won a smaller share of seats than votes due to the first-past-the-post system.