A one-party system imposed by law with all other parties proscribed is

Step 1: Analyze the question The question asks for the term for a one-party system that is imposed by law, where all other parties are banned (proscribed).

Step 2: Explain the concept There are two ways a one-party system can come about:

• De jure one-party system: "De jure" means "by law." The constitution or a statute formally makes only one party legal and bans all others. Examples include Ghana under Nkrumah after 1964, and Tanzania and Zambia in their one-party eras.
• De facto one-party system: "De facto" means "in fact." The law allows other parties, but one party is so dominant that the others have no real chance of winning power.

Step 3: Apply to the options

• A. Social party system: not a standard classification.
• B. De jure one-party system: matches. The one-party rule is established by law, and the other parties are legally prohibited.
• C. Communist political system: this describes an ideology and system of government. Communist states are often one-party, but the term does not specifically mean one-party rule imposed by law.
• D. Elitist party system: this refers to a party run by a small elite group, not to legal prohibition of other parties.

Step 4: Answer The key words "imposed by law" and "proscribed" point to de jure.

Exam tip: Remember "de jure = by law" and "de facto = in fact/in practice." When a question mentions legal imposition or a ban, think de jure. When it describes one party dominating in practice while others still exist legally, think de facto.