While not necessarily slaves, outlaws, illegal immigrants, or criminals, second-class citizens have significantly limited legal rights, civil rights and socioeconomic opportunities, and are often subject to mistreatment and exploitation at the hands of their putative superiors.
Systems with de facto second-class citizenry are widely regarded as violating human rights.
[4] There is much debate about where to draw the line on defining second-class citizenship and whether it amounts to statelessness, and the category remains unofficial and mostly academic.
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, Latvian and Estonian non-citizen minorities, 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.
A resident alien or foreign national, and children in general, fit most definitions of a second-class citizen.