South African elections in the 1980s

[Lord Halifax]

Alternatively, an eventual black takeover by force - with all that would have likely entailed.

(think late period Mugabe, but on steroids - and it could easily have been worse than that)

Seems unlikely given the strength of SADF, and the fact that whites made up a far bigger portion of the population than they ever did in Zimbabwe. It would have resulted in a genocide on the black population if they tried.