Public protector Thuli Madonsela has once again rubbished Police Minister Nathi Nhleko's report, which exonerated President Jacob Zuma of liability for the security upgrades to his Nkandla residence. Madonsela said Nhleko had no legal basis to review her findings or reinvestigate a matter that a Chapter 9 institution had already reached a decision on.She said: "It cannot be done with the auditor-general and it cannot be done for the [Independent] Elecoral Commission [or] others," she said.Madonsela said Nhleko "who exercises delegated authority, at the pleasure of the president, who is the sole repository for executive authority, cannot under the Executive Members' Ethics Act account to parliament on behalf of the president".Madonsela spoke to the press after the parliamentary ad-hoc committee deliberating on the Nkandla upgrades refused to allow her to speak during their proceedings.Madonsela said the proper protocol, in terms of section 3 of the Executive Members' Ethics Act, would be for Zuma to evaluate her report and give his full intentions regarding her office's report .She maintained Zuma was financially liable for the non-security features that formed a large part of the construction."I must indicate that my team and I are concerned that the safety valve an office such as ours is meant to provide by giving people a voice, and the state better ears, is being eroded," she said.Madonsela said she wondered what former president Nelson Mandela would have made of "this bizarre turn of events, considering that he once said 'even the most benevolent of governments were made up of people with all the propensities of human feelings'."University of South Africa constitutional law expert Professor Shadrack Gutto said a series of scandals - from Sudanese president Omar al-Bashir's easy escape from South Africa, despite a court barring his exit, to the Nkandla upgrades - posed a threat to our constitutional democracy.He said: "We are seeing the executive using institutions like parliament and ministers to really weaken the work of the vibrant institutions of constitutional democracy. I think we are sliding downhill and this should concern every citizen of this country."..