There are real limits to what President Cyril Ramaphosa's actions are within the realm of reason. He can't just act against those who oppose him, and he cannot just replace them with allies.

President Cyril Ramaphosa on Sunday promised that the renewal of the ANC was now "irreversible and irrevocable". There may be no better way for him to put his money where his mouth is than by conducting a major Cabinet reshuffle and removing those with big question marks against them.

But there are limits to how far he can go. Some of the questions a reshuffle poses are actually vexed political decisions that can have major repercussions. Within all of this, at least one person who is in Cabinet now, Mineral Resources and Energy Minister Gwede Mantashe, is likely to significantly enhance his political power and negative influence on South Africa's energy policy.

Normally, it is difficult to predict if, or when, a president will reshuffle their Cabinet. Changing a Cabinet is entirely within a president's power. They do not have to consult anyone, and those who are removed have no legal recourse -- they can only ask how high they need to jump.

There is no legal...