JOHANNESBURG (Reuters) - African National Congress (ANC) MP Makhosi Khoza, a strident critic of scandal-plagued President Jacob Zuma, quit South Africa s ruling party on Thursday, labeling Nelson Mandela s 105-year-old liberation movement  alien and corrupt . The 47-year-old Zulu linguistics expert, an ANC supporter since the age of 12, denounced Zuma in July as a  dishonorable and disgraceful leader  due to the litany of scandals he has attracted during his eight years in power. Her comments earned her death threats and a provincial party disciplinary hearing, but Khoza said she was not prepared to sit around and wait for the verdict from a party she said was willfully blind to the failings of its leader.  Why haven t we charged Zuma? Why are we charging Makhosi Khoza? We are making a mockery of the rule of law. We are making a mockery of the ANC constitution,  she said in an interview on the SABC, the state broadcaster.  Charge Zuma. Fire Zuma from the ANC, then I will know that you are serious about self-correcting.  Khoza is believed to have been one of around 30 ANC members of parliament who voted against Zuma in an ultimately unsuccessful Aug. 8 parliamentary no-confidence vote conducted by secret ballot. ANC spokesman Zizi Kodwa did not answer calls to his mobile phone. The most serious allegations against Zuma relate to his friendship with the Guptas, a family of Indian-born businessmen accused of using political influence to secure lucrative contracts with state-run companies and remain above the law. Zuma and the Guptas, who employ Zuma s son, Duduzane, as a director of at least one of their companies, have denied any wrongdoing and say they are the victims of a politically motivated witch-hunt. Zuma s time at the helm of the ANC comes to an end in December when the party chooses a new leader, although he will remain head of state until 2019 unless the ANC removes him early, as it did with President Thabo Mbeki in 2008. As Khoza fulminated on air, Zuma s former wife Nkosazana Dlamini-Zuma was sworn in behind closed doors as a member of parliament, cementing the belief she is his preferred successor against challengers led by Deputy President Cyril Ramaphosa. The parliamentary seat gives Dlamini-Zuma, ex-chairwoman of the African Union Commission in Addis Ababa, a platform from which to raise her profile ahead of December s party leadership conference. Separately, the Pretoria High Court delivered a blow to the Gupta s media-to-mining commercial empire, throwing out its attempt to block India s Bank of Baroda, the last bank in South Africa prepared to handle its money, from pulling the plug. Judge Hans Fabricius dedicated eight pages of his verdict to the allegations against the Guptas, questioning why police and prosecutors had failed to act despite years of stunning media revelations and numerous formal criminal complaints.  I could not help wonder whether, unbeknown to me, democracy and the rule of law had somehow been suspended,  he said, lamenting the decline from the optimism and idealism of the self-styled  Rainbow Nation  immediately after apartheid ended.  Could it be possible that the future, so bright in 1994, was now only history?  he continued.  Do the various investigating bodies of the police service ... still remember their constitutional duty to combat and investigate crime?  Gary Naidoo, editor of the Gupta-owned New Age newspaper and the family s de facto spokesman, was not available for comment. 