South Africans heaved a collective sigh of relief on Wednesday when Treasury veteran Pravin Gordhan presented a measured Budget designed to save the country from a potentially devastating credit downgrading to ''junk'' status.Though the initial reaction to the Budget was lukewarm - amid concerns that Gordhan had not cut enough state fat or introduced sufficient pro-growth measures - by Thursday there were signs that the market was favourably reviewing its position.Then came the hammer blow. Bemused citizens learned on Friday that, just a few days before he delivered the Budget, Gordhan had threatened to resign because of a power struggle with his tax chief.Tom Moyane, the SARS commissioner, had flouted the minister's instructions and had initiated an investigation by the Hawks into Gordhan's conduct when he headed the revenue service almost a decade ago.No surprises then that the rand plummeted on Friday, its biggest fall since 2011. Suddenly it was back to the future - in this case December last year when President Jacob Zuma's diabolical axing of the internationally respected Nhlanhla Nene as finance minister triggered a currency collapse.Zuma, who had appointed Moyane to ''clean up'' SARS, amid revelations about a ''rogue unit'' that apparently spied on powerful political figures, including the president himself, quickly issued a statement expressing full confidence in Gordhan.But the rand continued to bleed and was trading at R16.23 at one point on Friday.Zuma, who could not have looked favourably on Gordhan's comments about the president's appointment of ANC backbencher Des van Rooyen as finance minister as a ''coup'' attempt on the Treasury, now has a stark choice.He can allow Moyane to continue to thumb his nose at Gordhan, fire the minister or he can redeploy his man at SARS.The course he takes will likely decide his own political fate...