The party aligned itself closely with the Conservative Party and Liberal Unionists to campaign to prevent the passage of a new Home Rule Bill. Its MPs took the Conservative whip at Westminster, and its members were often described as 'Conservatives' or 'Conservative Unionists', even though much of its support came from former Liberal voters. Among its most prominent members were the Dublin barrister, Sir Edward Carson, and the founder of Ireland's cooperative movement, Sir Horace Plunkett. Its electoral strength was largely (although not exclusively) concentrated in east Ulster and south Dublin.