By appointing the chair and a majority of the members
Federal government but i am not sure completely
Candidate Party Electoral Votes
Abraham Lincoln Republican 180
John C. Breckinridge Democratic 72
John Bell Constitutional Union 39
Stephen A. Douglas Democratic 12
The primary issue with a one party system is the suppression of individual rights and no democratic rights.
In a one-party system, like the one in Communist China, the people have no voice in how the country is run. One political party makes all the decision without any opposition in the parliament.
From the perspective of human rights, this will lead to dictatorship and a curb on freedom of speech.