Conversation so far:
When did P.
W.
Botha enter Parliament?
At age 30, Botha was elected head of the National Party Youth in 1946.
What happened to him after that?
and two years later won a race for the House of Assembly.
When did he win that election?
1946, and two years later won.
Who was his opponent in that election?
CANNOTANSWER.
What happened to him after the 1948 election?
1958 Botha was appointed Deputy Minister of Internal Affairs.
What was his next position after being appointed as the Deputy Minister of Internal Affairs?
in 1961 advanced to Minister of Coloured Affairs.
What impact did he have in that position?
CANNOTANSWER.
What was his next position after being Minister of Coloured Affairs?
He was appointed Minister for Defence.
What was his impact there?
the South African Defence Force reached a zenith.

Question: How long was he a Minister for Defence?
Self-contained rewrite: How long was P. W. Botha a Minister for Defence?