Final answer:
Harold Cardinal wrote the Citizens Plus document to counter the Canadian government's 1969 White Paper by asserting the unique rights of First Nations as distinct citizens.
Step-by-step explanation:
The primary motivation for Harold Cardinal to write the Citizens Plus document, also known as the Red Paper, was to articulate a response to the Canadian government's 1969 White Paper. The White Paper proposed to eliminate Indian status, dissolve the Department of Indian Affairs, and transfer the responsibility for First Nations to the provinces. Cardinal, representing the Indian Association of Alberta, drafted Citizens Plus to assert Indigenous Peoples' rights and to counter the proposed assimilation policies. The document proposed recognition of First Nations as distinct citizens with unique rights. The Citizens Plus document aimed to address the inequality and promote the rights of Indigenous peoples in various aspects of Canadian society, such as education, employment, and government representation. This document was significant in highlighting the need for Indigenous rights and advocating for a more inclusive and equitable society.