There were three simultaneous tasks awaiting her when she walked out on stage in her tangerine pants suit. 

She had to dispel any notion that she was not now solidly with Barack Obama. Any sign of doubt would fuel efforts by the Republicans to chip away at his support and legitimacy as the Democratic nominee. 

She had to persuade her supporters that Obama would now carry forward the populist themes that had dominated her campaign, and get them fired up about taking on John McCain. 

She had to provide some sense of closure to women voters who had invested so deeply in her campaign, giving them a sense of achievement even in defeat. 

Clinton carried off all three challenges in a powerful speech that brought the hall to its feet.

The problem though for Clinton and the Democrats was not necessarily in the conventional hall where party delegates are experienced enough to recognise the need for moving on. 

Clinton had to make sure that her message carried to a wider audience of supporters - some relative newcomers to the political process - who are now threatening to vote for McCain. 

That constituency, loosely associated with the party is going to be hard to reach. They are also unlikely to be persuaded to give up after a night of watching Clinton appear so thoroughly in command - even presidential. 

But that is not entirely her fault. Clinton, true to form, was thorough. She left no doubt that she was now supporting Obama's campaign, and made a compelling intellectual argument that he would carry forward the issues she championed.