On Thursday, some of Hollywood's top stars and deepest pockets will congregate at the Studio City, Calif., home of actor George Clooney to mingle with President Obama and raise money for his re-election campaign.

It also will include at least a few noncelebrities. In a fundraising and attention-getting online promotion, the campaign cast the Clooney event as a lottery of sorts: A $3 donation included the chance to win "a free trip to L.A." and attend the star-studded reception.

Four years ago, Republican presidential candidate John McCain derided Obama for his celebrity friendships. But as the Los Angeles Times reports Thursday, some of those friendships have been strained over the past three years:

"As Obama's term has progressed, though, some Hollywood liberals have expressed disappointment that he has not been more forceful on issues such as the environment and closing Guantanamo Bay. And one policy important to many in the entertainment industry — legislation to curtail online piracy — has so far failed to find support in the White House."

Obama's campaign expects to raise as much as $6 million from the generally small online donations connected to the event, and millions more from those who are spending $40,000 each to dine with the president at Clooney's home, according to the Hollywood Reporter.

"One of the important reasons that celebrities have become more involved in politics has been their capacity to attract a crowd, and attract a crowd that's willing to put in whatever it is, ticket price or something more," said John Street, a politics professor who studies the phenomenon of celebrity politicians at the University of East Anglia in the United Kingdom. "The fact that you're seeing George Clooney ... is almost more important than anything else, and that's what those stars offer, a reason for the cameras to be there."

A recent attack ad from conservative superPAC American Crossroads — "Cool" — asks: "After four years of a celebrity president, is your life any better?"

Street says politicians have to walk a fine line between celebrity and leader.

"There is a strong belief in a sense that this is undignified behavior, that this sort of stuff is in a way dumbing down politics and is trivializing the office," said Street. "Overplaying the celebrity hand can lead to embarrassment as much as it can lead to popular cool success."

In 1992, Bill Clinton perhaps set the standard for politicians capable of embracing the celebrity spotlight when he appeared on The Arsenio Hall Show playing a saxophone.

Like Clinton and many politicians, Obama can be a bit of an entertainer when it serves his purposes. He showed that during his first run for the White House, from dancing onstage with Ellen DeGeneres to campaigning with Oprah Winfrey.

Street — who calls Obama "one of the biggest celebrities on the planet at the moment" — notes that he is "always able to put a distance between himself and whatever performance he's giving. He knows he's playing a game. He knows this is a bit of light relief, a bit of entertainment, but he keeps his dignity ... and that seems to me a very clever trick. It speaks to him as a very sharp political operator."

Of course, using show business for political gain is a nonpartisan phenomenon. Before the 2008 election, the complete Republican ticket, McCain and vice presidential nominee Sarah Palin, appeared on NBC's Saturday Night Live.

And in March, Mitt Romney played vice presidential word association with Jay Leno when appearing on NBC's The Tonight Show.

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Source: NPR