AMERICA:AT NEW York's Radio City Hall this week Elton John took a moment between songs to share his analysis of why Hillary Clinton is trailing Barack Obama in the Democratic presidential race.
"I'm amazed by the misogynistic attitudes of some of the people in this country. And I say to hell with them," he said. "I love you, Hillary."
Clinton beamed as she appeared onstage with husband Bill and daughter Chelsea, declaring that she could indeed "feel the love tonight" before reassuring supporters that "I'm still standing".
The concert brought in a badly-needed $2.5 million to the Clinton campaign, which is being vastly outspent by Obama. It remains to be seen if John's support for Clinton attracts many new voters, but if other celebrity endorsements are anything to go by, it probably won't.
When Oprah Winfrey endorsed Obama last year, many analysts expected the queen of daytime TV to persuade huge numbers of women to desert Clinton. Oprah campaigned in four states - Iowa, New Hampshire, South Carolina and California - two of which Obama won and two of which he lost.
Eight per cent of voters said Oprah's endorsement made them more likely to support Obama, 10 per cent said it turned them off the candidate and 82 per cent said it made no difference.
If Oprah's support for Obama has made little difference to his popularity, it may have had a dramatic effect on her own, according to Costas Panagopoulos, an assistant professor of political science at New York's Fordham University.
Writing in Politico, Panagopoulos notes that Oprah's popularity had been remarkably consistent since she launched her daily talk show more than 20 years ago.
"Ten years following the launch of her talk show, the January 1996 Survey on American Political Culture found that more than three-quarters (78 per cent) of Americans held a favourable opinion of Oprah," he writes.
"Survey data suggests Americans held Oprah in high regard throughout the decade that followed. In December 1997 an NBC News and Wall Street Journal poll showed that more Americans admired Oprah than President Bill Clinton, former president Ronald Reagan and Microsoft founder Bill Gates, an icon at the height of the dot-com boom."
In a 1999 poll which asked people to identify the 20th century women they most admired, 26 per cent chose Oprah, putting her behind Mother Teresa but ahead of everyone else, including Marie Curie and Rosa Parks.
In January last year 74 per cent of Americans still said they had a favourable view of Oprah, but in May she announced to CNN's Larry King that Obama would be the first presidential candidate she had ever endorsed.
"Almost instantly, Oprah's popularity in America plummeted," Panagopoulos writes.
"An August 2007 CBS News poll showed only 61 per cent of Americans were favourably disposed to her - a considerable drop of 13 percentage points from a similar survey conducted just seven months prior."
Once she started campaigning for Obama in December, her popularity fell further, and just before Christmas she had a 55 per cent approval rating - her lowest ever.
Last month, an AOL television survey of 1.35 million viewers found that Oprah was losing ground in daytime TV, with 46 per cent of respondents identifying rival Ellen DeGeneres as the host who "made their day", compared to just 19 per cent for Oprah.
"To be sure, Oprah remains one of the most popular figures in America, but recent data suggests her popularity has eroded," Panagopoulos writes. "One possible explanation for this decline is that her endorsement of Obama and her support for him may have done more to damage impressions of her than to strengthen support for Obama."
Oprah has spoken about angry letters she received from Clinton supporters accusing her of betraying her sex by not endorsing the woman candidate, and she was also prepared to alienate some Republican supporters. Panagopoulos suggests, however, that the reason some fans feel alienated by celebrity endorsements may have less to do with political partisanship than with the public's view of the celebrity's proper role.
"While celebrities are certainly entitled to express their political beliefs - just like every other American - it is possible that the public prefers high-profile entertainment personalities to stay on the tube and off the stump," he writes.
