Bill Clinton's announcement, at a White House press conference, amounts to an open-ended United States commitment to keep troops in Bosnia for as long as it takes for peace to become - in his words - "self-sustaining". While insisting that the presence would not be permanent, Mr Clinton would not guarantee that the troops would be home even by the time he leaves office in January 2001.
In a rare admission for a politician, the US President said he had been "mistaken" in thinking that the Nato-led contingent would no longer be necessary after next June and said he did not want to repeat the error. However, the necessary Senate approval is likely to be granted only grudgingly and after acrimonious debate.
Mr Clinton - who will visit to US servicemen in Bosnia this weekend - said that in future there should be "achievable, concrete benchmarks, not a deadline" for the withdrawal of troops. These included a trained civilian police force, functioning independent media and the return of more refugees. The setting of "benchmarks" represents a big tactical change.
The night before Mr Clinton spoke, Nato troops in Bosnia staged a dramatic dawn raid to capture two more men - this time Croats - wanted for war crimes at the international tribunal in The Hague.
A Dutch commando unit crept into the village of Santici to the house belonging to Vlatko Kupreskic and then, as the signal was given, burst in. The man they were tracking has been charged with involvement in one of the most callous massacres of the war - the murder of more than 100 Muslim civilians in the village of Ahmici, near Vitez in central Bosnia, in April 1993. He had been living quite openly in the area ever since. Mr Kupreskic was shot at least three times in the chest, arm and leg.
He was then whisked off to Sarajevo for emergency surgery, and once it was clear that his life was not in danger he was flown to The Hague.
The second arrest was an altogether quieter affair. Anto Furudzija did not know he was wanted by the international tribunal - his was a so-called "sealed" indictment - and he gave himself up without resistance. It was not clear last night what the nature of the charges against him might be.