Conversation so far:
When did P. W. Botha enter Parliament?
1948
What happened to P. W. Botha after entering Parliament?
In 1958 Botha was appointed Deputy Minister of Internal Affairs by Hendrik Verwoerd.
When did P. W. Botha win the the 1948 election?
1948
Who was P. W. Botha's opponent in the 1948 election?
JP Marais
What happened to P. W. Botha after the 1948 election?
In 1958 Botha was appointed Deputy Minister of Internal Affairs by Hendrik Verwoerd.
What was P. W. Botha's next position after being appointed as the Deputy Minister of Internal Affairs?
Minister of Coloured Affairs
What was P. W. Botha's next position after being Minister of Coloured Affairs?
P. W. Botha was appointed Minister for Defence by Verwoerd's successor B.J. Vorster, upon Verwoerd's murder, in 1966.

Question: What was his impact there?
Self-contained rewrite: What was P. W. Botha's impact as Minister for Defence?