Until a few weeks ago, US officials said Washington would only recognise the Luanda government when it reached agreement with Unita. They also appeared to be using the 'threat' of recognition to persuade Unita to reach a ceasefire agreement. But Wednesday's statement indicates that they have become exasperated with Unita's intransigence.
The talks in Abidjan are held up by Unita's refusal to withdraw from towns it has seized since relaunching the civil war in October. Unita resumed fighting after it lost the United Nations-monitored elections in September, which it denounced as fraudulent. The UN and the US accepted the results but Unita troops attacked government forces throughout the country and fighting is reported to be continuing in the north and east.
Jorge Valentim, leader of the Unita delegation at the peace talks, said: 'The US decision will embolden the MPLA's negotiators in Abidjan and give them the impression they can now stall the negotiations.'
But observers at the talks said it was Unita that was holding up the talks, and the movement's desperation is reflected in Unita Radio's recent appeal against US recognition. It said the elections were rigged, and added: 'US standards of justice are not consistent with recognition of the fraudulent, Communist and genocidal Luanda government.'
But Mr Clinton, announcing recognition, said: 'It is my hope Unita will accept a negotiated peace settlement and it will be part of this government.'
Recognition also closes an unfortunate chapter of US policy in Africa, in which it backed a movement it believed to be democratic and to have majority support, but which refused to accept the results of an election which it lost.
From 1975, when the US-backed movements, Unita and the FNLA, were defeated by the Cuban-backed MPLA, Washington refused to recognise the MPLA but the Clark Amendment banned US military support for Angolan political movements. Washington said it would not recognise the MPLA until Cuban troops were removed from Angola.
Then, in 1985, the Clark Amendment was repealed, allowing the Reagan administration to give Unita up to dollars 20m ( pounds 13m) worth of military equipment including Stinger anti-aircraft missiles.
When Luanda agreed to dispense with its Cuban allies and talk to Unita, the price of US recognition was changed to include democratic elections. When these were held, there was no recognition even when the MPLA accepted the results and Unita rejected them.