What is Sovereignty?
According to the Merriam-Webster dictionary, sovereignty refers to unlimited power over a country, and/or a country's independent authority and the right to govern itself. The idea of sovereign "states" emerged out of the Treaty of Westphalia in 1648, which bounded authority to certain borders of a specified territory . Concepts that relate to sovereignty include self-determination and autonomy, which both illustrate the amount and effect of external control over a state. This system of state sovereignty spread over the world with European colonization , though this is a contested reality for the original inhabitants of the land colonized by the Europeans.
Sovereignty and Terra Nullius
The principle of terra nullius is internationally recognized as a manner through which land belonging to no one could be seized; it was used under colonialization with reinforcement from the Doctrine of Discovery (Permanent Forum on Indigenous Issues, May 2012). According to Robert A. Williams Jr., the Doctrine of Discovery is "based invalidly on racial superiority of Christian Europeans, compounded by regulations (Requerimiento), “discovery” used as framework for justification to “dehumanize, exploit, enslave and subjugate indigenous peoples and dispossess them of their most basic rights, laws, spirituality, worldviews and governance and their lands and resources”…ultimately the very foundation of genocide" .
This undermined the sovereignty of indigenous groups residing in regions, as terra nullius could only be imposed in regions "belonging to no one". It was one of the first instances of an international "law", deriving its power from Papal Bulls of the 15th century. In the context of European colonization of the Americas, it allowed for 'ownership' of the 'land' by the hands of Christian colonizers because the indigenous people were seen as "pagan" and therefore not worthy of the land . Such a doctrine shaped much of what is known of US law in regards to different court cases in the 18th century, ruling that the European Christian colonizers had a "right" to the land, "notwithstanding 'the natives, who were heathens".  This denied indigenous people sovereignty (authority over their territory) as well as any right to self-determination .
Doctrine of Discovery and Current Injustice
This right to self-determination resulted from an effort to make reparations for damages to indigenous autonomy and sovereignty during the period of colonialism. The United National Declaration on the Rights of Indigenous Peoples states that "indigenous peoples have suffered from historic injustices as a result of, inter alia, their colonization and dispossession of their lands, territories and resources, thus preventing them from exercising, in particular, their right to development in accordance with their own needs and interests". The Doctrine of Discovery was "used for centuries to expropriate indigenous lands and facilitate their transfer to colonizing or dominating nations" . Though the Doctrine has been repudiated by the United Nations, its lasting effects are still seen. This becomes particularly relevant when considering a concept like self-determination, considering its ambiguity and the difficult history of application to indigenous peoples .
The Doctrine of Discovery is a piece of international legislation still in place today. Although nearly all lands have been accounted for by a particular nation, the right of claim to lands is still limited to Western, Christian, nations. In order to comply with contemporary standards of human rights, there are calls to repeal the Doctrine of Discovery as proclamations that declare indigenous peoples as "less than human".  Such instances where the Doctrine of Discovery is still legitimate need to instead be replaced with contemporary standards of human rights and international indigenous rights (UN Term).
Contemporary Sovereignty Issues and Indigenous Peoples
The United Nations Declaration on the Rights of Indigenous Peoples affirms the "fundamental importance of the right to self-determination of all peoples", and further specifies that "indigenous peoples have the right to self-determination. By virtue of that right they freely determine their political status and freely pursue their economic, social and cultural development". However, the issue of indigenous peoples, groups, and tribes struggling to gain and/or maintain sovereignty is often the foundation through which other issues arise, including the struggle for indigenous environmental and land rights . As such, many indigenous groups are unable to truly live in an autonomous manner, without some influence of, or reliance upon, the society in which they reside.
Terra Nullius in Indigenous Cases
- Mabo (Australia)
In 1992, the High Court of Australia recognized Mabo indigenous title to land, and famously rejected both terra nullius and the Doctrine of Discovery. 
- British Columbia (Canada)
A 2010 case illustrated that Canada's policies and authority surrounding indigenous rights and land claims is still largely based in authorities stemming from ownership via the Doctrine of Discovery and terra nullius. 
- Awas Tigni (Nicaragua)
Nicaragua was found to have violated multiple human rights through articles of the American Convention on Human Rights; specifically due to their failure to recognize land of Awas Tigni indigenous community. 
= Sovereignty in post colonial states=
- http://www.jstor.org/discover/10.2307/845989?uid=3737720&uid=2129&uid=2&uid=70&uid=4&sid=21104936981907 The American Indian in Western Legal Thought; 1990
- http://www.un.org/press/en/2012/hr5088.doc.htm Permanent Forum on Indigenous Issues, May 2012
- http://web.uvic.ca/igov/research/pdfs/audrey_roy_thesisfinal.pdf Roy, 1998