* Strong union rhetoric makes debate, not policy

* ANC only likely to court unions before elections

* Calls for union 'oligarchs' to keep out of government

By Ed Cropley

JOHANNESBURG, Sept 25 (Reuters) - It often attracts the epithet "powerful", but on the evidence of this week's triennial conference, the only truly powerful thing about the Congress of South African Trade Unions (COSATU) is its rhetoric.

For four days, leaders of the union body that played a key role in the anti-apartheid struggle berated their red-shirted comrades about the perils of bourgeois capitalism and the need to "build working class power in all sites of power".

Yet its stamp on policy is more noticeable by its absence, even though COSATU sees new president Jacob Zuma as "its man", having backed him in a 2007 internal putsch against the avowedly pro-business Thabo Mbeki as head of the ruling ANC.

With an election not due again until 2014, analysts say the ANC is only likely to pay lip-service to its junior partner in an alliance that also includes the Communist Party, another anti-apartheid actor with an identity crisis 15 years after the end of white minority rule.