Workers attend a May Day rally in Bloemfontein, South Africa, Monday, May 1, 2017. South African President Jacob Zuma was jeered by labor unionists and his speech was cancelled after scuffles broke out between his supporters and workers chanting for him to step down at the rally.Khothatso Mokone/The Associated Press
It was a humiliating defeat for South Africa's President: jeered off the stage, forced to abandon a major televised event before he could deliver his traditional May Day speech to his long-time allies in the country's biggest trade-union federation.
Jacob Zuma suffered perhaps the biggest embarrassment of his eight-year presidency on Monday as he was obliged to make a hasty exit from the stage. "Zuma must go," some union members chanted loudly. "Zuma must fall."
The Congress of South African Trade Unions has been a formal alliance partner of the ruling party, the African National Congress, for the past 27 years. But now, it has joined the growing chorus of demands for Mr. Zuma's resignation.
Read more: South Africa's Jacob Zuma holds the key to Africa's political future
His unexpected departure from the union rally in Bloemfontein, capital of the Free State, was one of the clearest signs of Mr. Zuma's crumbling support after years of corruption scandals. In the 23 years since apartheid ended and democracy began, it was the first time that an ANC leader was booed off the stage at a May Day rally, analysts said.
Two other senior ANC officials who support Mr. Zuma were similarly jeered and drowned out by union members when they attempted to speak at separate May Day rallies in other cities on Monday, while two of his ANC rivals were cheered at their own May Day events.
One poll this year found that Mr. Zuma was supported by only 20 per cent of South Africans in the seven biggest cities. Even within his ruling party, several of the top leaders have openly criticized Mr. Zuma for his recent cabinet purge and his decision to sack his widely respected finance minister.
Deputy president Cyril Ramaphosa, unofficially campaigning to replace Mr. Zuma, has been increasingly critical of government corruption and has called for a judicial inquiry into allegations that Mr. Zuma's close friends and business allies, the Gupta brothers, have controlled government appointments and offered bribes to senior officials.
As the divisions grow deeper and more bitter within the ANC and its traditional allies, Mr. Zuma may find it increasingly difficult to maintain power and orchestrate a handover to his chosen successor, his former wife, Nkosazana Dlamini-Zuma. And there are mounting fears that his loyalists could increasingly turn to violent tactics to ensure his control over the country.
Recent months have seen a growing number of political killings, death threats to Zuma opponents, ominous talk of shadowy enemies and mysterious break-ins at the offices of those who challenge the government.
Even the ANC has expressed its alarm at the trend. "The African National Congress is concerned at what appears to be a climate of intimidation steadily encroaching into South Africa's body politic," the party said in a recent official statement, without identifying the perpetrators of the threats.
There are growing reports of intimidation against "political leaders, activists and journalists," the ANC said. "Political intolerance would take South Africa back to a painful past that should not be repeated."
The worrisome signs have included an unsolved break-in and computer theft at the office of South Africa's chief justice after the highest court had repeatedly issued rulings against Mr. Zuma. Death threats have been received by investigative journalists, independent police investigators and ANC rivals of Mr. Zuma.
In the most hotly contested province, Mr. Zuma's stronghold of KwaZulu-Natal, there have been 35 political assassinations reported in the past year. Analysts have blamed the murders on factional fighting within the ANC.
Equally disturbing has been the increased use of official state agencies and thuggish groups of ANC supporters to target Mr. Zuma's political enemies.
One of Mr. Zuma's biggest rivals, the former finance minister Pravin Gordhan, was repeatedly subjected to investigations and criminal charges by Mr. Zuma's loyalists in the police and national prosecuting agency.
When he fired Mr. Gordhan last month, Mr. Zuma reportedly justified it by citing a fake "intelligence dossier" with fictional allegations against the finance minister. Mr. Zuma's state security minister has alleged that "rogue elements" are trying to use the judiciary and civil society to "destabilize" the country.
In another ominous sign, Mr. Zuma ordered the deployment of more than 440 soldiers to protect Parliament during his annual state-of-the-nation speech this year. Members of Parliament from an opposition party were attacked by security guards and violently ejected from the parliamentary chamber when they disrupted Mr. Zuma's speech.
In an earlier incident, the police threatened to file treason charges against students who had protested outside Parliament. And another Zuma loyalist, the national police commissioner, recently suggested that the anti-Zuma marches in South Africa's capital were illegal, despite a court ruling that allowed the protests.
In local elections last year, opposition parties gained control of city councils in Johannesburg and other main cities. But since then, violent groups of ANC supporters have repeatedly disrupted the council meetings, hurling bottles and inflicting violence on opposition officials.
In Johannesburg, thuggish groups of Zuma supporters have disrupted peaceful protests against the Gupta family by menacingly waving sticks and tearing up protest placards. The Guptas, meanwhile, deployed an armoured vehicle to protect their home – despite media reports that the vehicle was illegal.
As the political tensions rise, more than 70,000 protesters took to the streets of South Africa last month to demand Mr. Zuma's departure. In response, hundreds of ANC supporters in camouflage uniforms surrounded the ANC headquarters in Johannesburg, just a few blocks from the protesters.
The uniformed supporters were officially described as "military veterans" although most were too young to have served in the ANC's military wing during the anti-apartheid struggle. The "military veterans" also attended Mr. Zuma's birthday party a few days later in a show of solidarity with him.
A leading political writer, Stephen Grootes, has described this as a frightening attempt to "militarize our politics." In a recent commentary, he asked: "What kind of president does not take action when a private political army starts to walk the streets?"
Geoffrey York