The Monroe Doctrine was an attempt by the United States to delineate what the US would and would not get involved in as a country. In essence, it is a declaration that the US would stay out of land wars in Europe if Europe stayed out of the affairs of the Western hemisphere.
The prime minister of Ghana was the head of government of Ghana from 1957 to 1960 and again from 1969 to 1972. Wikipedia
First holder: Kwame Nkrumah
Abolished: 13 January 1972
Final holder: Kofi Abrefa Busia