AT A New York party, Barack Obama proved once again last week that he had the fundraising ability, star power and magnetism to rival Hillary Clinton’s presidential campaign juggernaut.

Tina Brown, the former editor of Vanity Fair magazine, Naomi Watts, the movie star, and Theodore Sorenson, once John F Kennedy’s speech-writer, were among the glitterati. But what the guests wanted to know was: does Obama have the staying power to win the Democratic nomination?

To Democrats expecting repeats of his breathtaking speech to the 2004 party convention, which launched his national political career, Obama has appeared low-key and tired at times during the early stages of his campaign.

In meetings across the country he rarely wins more than one or two polite standing ovations. One Hollywood supporter recently noted that the crowd at one of his events “seemed to me unmoved, frankly” and “Barack seemed a little tired, to be honest”.

A Gallup poll on Friday, taken as news of an astonishing $25m (£12.6m) fundraising haul was announced, showed support for him at 19%, well behind Clinton on 38%.

“The survey result suggests that while Obama may have had a great deal of financial momentum in the past quarter, it was not matched by any increase in voter support,” Gallup reported.

Pressure is growing on the Illinois senator to unveil more policies. While Sorenson said that Obama reminded him of the young Kennedy, another guest said: “It’s all very well to talk about hope and idealism and values, but what about specific programmes?”

Clinton prepared to go on the offensive against Obama on his lack of policy details after he secured 50,000 more individual donors than her — an indication of his grassroots support.

Some Clinton donors have defected to Obama despite the “you are either with us or against us” tactics from her camp. Alan Solomont, a former Democrat party finance chairman and a favoured guest at the Clinton White House, said “people are ready for a new generation, a new face and a new voice”.

Times Recommends

• Times Charity Appeal: SolarAid
• Is it Black Monday all over again for Dubai?
• Behind the scenes at the biggest deal