Smash hit

He may take the fight to the Democratic credentials committee this month — or even on to the floor of the convention. Her supporters, many of whom pledged to vote for Mr McCain if she is not the Democratic nominee, chanted: “Denver! Denver!” at the end of the meeting.

Terry McAuliffe, the campaign’s national chairman, was more circumspect, saying: “This race goes on until someone meets the magic number to be the nominee of the Democratic Party.” Asked if she would protest against the decision on Michigan at the credentials committee, he replied: “Well, clearly we’re going to keep our options open.”

There are said to be divisions within her inner circle about how long to fight on. Some fear that Mrs Clinton may damage her prospects of a political future in the Senate — or elsewhere — if she is seen as dividing the party before the general election.

Others believe that she should use her vast support as leverage to secure promises of a senior position in Mr Obama’s Administration or the Senate — even the vice-presidential slot.

A new advertisement running in South Dakota highlighted how “17 million Americans” had backed Mrs Clinton, as aides once more predicted she would end up ahead of Mr Obama in the popular vote — even though turnout in Puerto Rico was far lower than the one million-plus once predicted.

Last night she told her rally in San Juan that the voices of people in Puerto Rico had deserved to be heard, before paying tribute to Mr Obama — whose name attracted boos from her crowd. "Even though people tried to tell you that your votes would not count you voted for the person who you believe will be the strongest nominee and the strongest president," she said.

Many Democrats argue that her strength among key sections of voters can help overcome Mr Obama’s potential vulnerabilities as a general election candidate, particularly among the white working-class. It is also still possible to find die-hard supporters who think that she will step in if he implodes before the convention.

This group was given fresh ammunition over the weekend by renewed controversy around his Chicago church, where the Rev Jeremiah Wright had previously delivered racially charged and anti-American sermons. Videos have circulated widely showing a guest speaker, the Rev Michael Pfleger, last week mocking Mrs Clinton as crying with self-pity, saying: “I’m white! I’m entitled! There’s a black man stealing my show!”

Mr Obama swiftly sought to limit the damage on Saturday by announcing, with “some sadness”, that he and his family were leaving the church where he had “found Jesus Christ” 20 years ago.

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