NEW YORK — Speaking to a New York City auditorium packed with unionists on Friday, the head of one of South Africa’s more radical labor unions delivered a wide-ranging speech in which he explained why he was backing a new, explicitly anti-capitalist "party of the working class" to challenge South Africa's ruling African National Congress (ANC).

“Because we live under a system of greed, a tiny minority that does not work, that lives by supervising, that does not produce labor surplus value, actually takes to itself the social surplus the working class produces,” said Irvin Jim, head of the National Union of Metalworkers in South Africa (NUMSA). "I must say that South Africa is not different."

The New York auditorium, owned by the labor union SEIU 1199, was Jim’s second stop in the United States last week. A day earlier, he spoke in Washington, D.C. at the left-wing cafe Busboys and Poets, where he was joined by actor Danny Glover and members of the Coalition of Black Trade Unionists (CBTU).

Jim’s brief speaking tour through the U.S. comes just two months after NUMSA was expelled from the Congress of South African Trade Unions (COSATU) for violating the trade federation’s constitution.

Among NUMSA’s offenses, according to COSATU, was the metalworkers union’s decision not to support South African President Jacob Zuma during his reelection campaign. Zuma belongs to the ANC, the party that has governed South Africa since the end of apartheid, and which has maintained power in part through a three-way alliance with COSATU and the South African Communist Party.

With NUMSA’s expulsion from COSATU, a growing seam in South Africa’s governing coalition burst wide open. Jim and the union he leads are now involved in efforts to create an ANC alternative they call the United Front.

“NUMSA says we are not a political party,” said Jim. “But we will be a catalyst for the organization of a united front, to link shop-floor struggles with community struggles."

In his New York speech — peppered with Marxist aphorisms — Jim explained why he felt a new party was necessary. By toppling the apartheid system, the ANC and its allies were successful in extending formal political rights to the country’s black population. However, economic inequality not only persists, he said, but seems to have increased since the fall of apartheid in 1994, according to the measure of inequality known as the Gini coefficient.

Jim lays much of the blame at the feet of the ANC, which has adopted an economic approach known as Growth Employment and Redistribution (GEAR ). To Jim, the GEAR strategy — with its reliance on tamping down deficits and attracting foreign investment — is tantamount to an embrace of globalization and neoliberalism.

The rupture between COSATU and NUMSA was, in part, the result of internal disagreements regarding their dealings with the ANC. Sean Jacobs, an assistant professor of international affairs at the New School and a South Africa native, said COSATU has a relationship with the ANC similar to the tense alliance between the Democrats and the U.S. trade federation AFL-CIO.

“They fight,” said Jacobs of COSATU. “But in the end they go with the Democratic Party."

NUMSA, on the other hand, has broken with both COSATU and the ANC to start what Jim describes as a party of the working class: the United Front. The name of that new party is a callback to the United Democratic Front (UDF), an anti-apartheid group from the 1980s. Whereas the ANC is “really a nationalist movement,” said Jacobs, the UDF was always, “more socialist, not anti-Communist, but anti-Soviet Union.” The United Front would carry on that tradition.

As for why Jim would take that message to U.S. labor unions: “It’s very obvious they’re trying to raise money in the United States and influence opinion here,” said Jacobs. “I think he’s coming to say, ‘look, if you’re hearing stuff about this United Front and what NUMSA’s trying to do, I’m here to explain it to you guys.’"

But when Jim was asked what U.S. labor unions should do to help NUMSA and the United Front, he demurred.

“Quite frankly, the struggle we’re championing does not belong to me,” he said. “It belongs to the working class and the poor."