President Thabo Mbeki has the toughest assignment of his presidency facing him this week.

His deputy, though he has not been found guilty of a crime, is implicated in corruption involving a convicted fraudster.

Mbeki, and the ruling African National Congress (ANC), have to decide what precisely to do with Deputy President Jacob Zuma.

The president is not in any way bound to await the outcome of a legal process to deal with possible malfeasance from his deputy. Constitutionally, Zuma serves — like all cabinet appointees — at Mbeki’s pleasure.

It remains the decision of national prosecutions chief Vusi Pikoli whether to charge Zuma with corruption or not. But the decision whether Zuma continues to serve in high government office is Mbeki’s alone.

Unlike the ANC, the president does not have the luxury of hiding behind process with the stakes so high. He must either fire Zuma or risk damaging his government even further by doing nothing.

Faced with such a choice, his first instinct will be to rid himself of Zuma, but therein lies the conundrum. Firing Zuma is likely to ignite a powder keg in the already polarised ANC. Mistrust and paranoia — fuelled by tit-for-tat backstabbing — has never been so ripe in the ANC.

Mbeki cannot pretend that ANC unity is not at issue when he makes his decisions.

As a second-term president, it might be less risky for Mbeki to take on Zuma and his followers head-on. But for many senior ANC leaders hoping for a political future beyond the Mbeki presidency, things are less clear cut.

Mbeki might be facing a kind of political endgame this week. If precedent is anything to go by, you can bet on Mbeki risking everything and going the distance with his opponents.

It will be up to those in the Zuma camp to decide whether they are equally willing to bring matters to a head.

With acknowledgements to Vukani Mde, Karima Brown and the Business Day.