In my view, politics is about power; that is its nature and how I approach and look at the subject. This does not mean ethics has no role whatever and principle is always ignored.
But how and when they are ignored or observed is, inescapably, a matter of judgment for politicians, not one of obligation. Judgment of the situation is the essence of the politician's job; the successful politician is the one who gets it right more often than wrong.
I would say, by way of clarification, that the same judgment applies in business. Business is by no means a smash-and-grab affair, a game for 'a pack of crooks'. But neither is it a game for the naive or the saintly. To succeed, you have to know the 'rules' - or the lack of them. That is why successful business people are said to have a natural 'instinct' for business while others simply cannot get it right. Judgment, not ethics, not intelligence, nor even diligence, rules.
In the present case, Ms Zille, who I take to be a highly professional and principled politician, committed an error of judgment with her initial tweet. There was nothing extraordinary about that; we all make mistakes and very many of them are made in a careless moment on the internet.
But in her response she has probably made it a terminal mistake. She has set herself against the party she has played a leading role in building, which is to say she has divided it, and plunged its black leader into a terrible dilemma that was none of his making but which he must now address because it is his job.
As the bitter reaction of many Democratic Alliance members and supporters shows, Mmusi Maimane cannot win: he must disappoint or outrage some as he gives others the satisfaction of saying he has done the right thing. Motives are suspect and challenged, loyalties on raw display.
These arguments will continue, of course, and so they should. I am interested above all in how politics shapes things, not in declaring who is in the right. All of us will see in time the one if not the other.