Sectarianism can be defined as a practice that is created over a period of time through consistent social, cultural and political habits leading to the formation of group solidarity that is dependent upon practices of inclusion and exclusion. Sectarian discrimination focuses on the exclusion aspect of sectarianism and can be defined as 'hatred arising from attaching importance to perceived differences between subdivisions within a group', for example the different denominations of a religion or the factions of a political belief.
Sectarian discrimination is commonly an underlying factor in periods of sectarian violence. Sectarian violence can be characterised as a conflict either between or among groups with specific ethnicity or religion, where the reason for the violence is their differences. An example of sectarian violence is the conflict between Catholics and Protestants in Northern Ireland.
Europe
Since the 17th century, there has been sectarian conflict of varying intensity in Ireland. This religious sectarianism is bound up with nationalism. This has been particularly intense in Northern Ireland since the 17th century. Due to Irish emigration these tensions can be found in other regions of the world, including Scotland (with some fans of football clubs such as Rangers and Celtic and Hearts and Hibs indulging in sectarian chants) (see: Sectarianism in Glasgow), Newfoundland, Canada's Maritime provinces, New York State, Ontario, Liverpool, Birmingham and elsewhere. See also Know-Nothings for anti-Catholic sentiment in the United States.
In Catholic countries, Protestants have historically been persecuted as heretics. For example, the substantial Protestant population of France (the Huguenots) was expelled from the kingdom in the 1680s following the revocation of the Edict of Nantes. Many Huguenots fled over the Channel to England in hope of a better life. In Spain, the Inquisition sought to root out not only Protestantism but also crypto-Jews and crypto-Muslims (moriscos); elsewhere the Papal Inquisition held similar goals.
In most places where Protestantism is the majority or 'official' religion, there have been examples of Catholics being persecuted. In countries where the Reformation was successful, this often lay in the perception that Catholics retained allegiance to a 'foreign' power (the Papacy), causing them to be regarded with suspicion. Sometimes this mistrust manifested itself in Catholics being subjected to restrictions and discrimination, which itself led to further conflict. For example, before Catholic Emancipation in 1829, Catholics were forbidden from voting, standing for election and buying land in Ireland.
Today, bigotry and discrimination in employment are usually relegated a few places where extreme forms of religion are the norm, or in areas with a long history of sectarian violence and tension, such as Northern Ireland (especially in terms of employment; however, this is dying out in this jurisdiction, thanks to strictly-enforced legislation. Reverse discrimination now takes place in terms of employment quotas which are now applied). In places where more 'moderate' forms of Protestantism (such as Anglicanism / Episcopalianism) prevail, the two traditions do not become polarised against each other, and usually co-exist peacefully. Especially in England, sectarianism is nowadays almost unheard of. However, in Western Scotland (where Calvinism and Presbyterianism are the norm) sectarian divisions can still sometimes arise between Catholics and Protestants. Indeed, in the early years following the Scottish Reformation there was actually internal sectarian tension between Church of Scotland Presbyterians and 'High Church' Anglicans, whom they regarded as having retained too many attitudes and practices from the Catholic era. Northern Ireland has introduced a Private Day of Reflection, since 2007, to mark the transition to a post-[sectarian] conflict society, an initiative of the cross-community Healing through Remembering organisation and research project.
The civil wars in the Balkans which followed the breakup of Yugoslavia have been heavily tinged with sectarianism. Croats and Slovenes have traditionally been Catholic, Serbs and Macedonians Eastern Orthodox, and Bosniaks and the majority of Albanians Muslim. Religious affiliation served as a marker of group identity in this conflict, despite relatively low rates of religious practice and belief among these various ethnic groups after decades of Communism.
Australia
Sectarianism in Australia is a historical legacy from the 18th, 19th and 20th centuries.