Before revision: Governments will typically deny the existence of a second class within its polity, and as an informal category, second-class citizenship is not objectively measured, but cases such as the Southern United States under racial segregation and Jim Crow laws, the repression of Aboriginal citizens in Australia prior to 1967, deported ethnic groups designated as "special settlers" in the Soviet Union, the Apartheid regime in South Africa, women in Saudi Arabia under Saudi Sharia law, LGBT people in countries that do not allow same-sex marriage, or outright criminalize consensual same-sex sexual relations, and Roman Catholics in Northern Ireland during the Parliamentary era are all examples of groups that have been historically described as having second-class citizenry and being victims of state-sponsored discrimination.
After revision: Governments will typically deny the existence of a second class within its polity, and as an informal category, second-class citizenship is not objectively measured, but cases such as the Southern United States under racial segregation and Jim Crow laws, the repression of Aboriginal citizens in Australia prior to 1967, deported ethnic groups designated as "special settlers" in the Soviet Union, the Apartheid regime in South Africa, women in Saudi Arabia under Saudi Sharia law, and Roman Catholics in Northern Ireland during the Parliamentary era are all examples of groups that have been historically described as having second-class citizenry and being victims of state-sponsored discrimination.