Effective celebrity activists use their fame and fortune to bring attention to important issues and to give credibility to legitimate representatives of social movements. Internationally-known celebrities can help expose and highlight problems which would normally get little or no news coverage without their involvement.

But does celebrity involvement really make any difference in what people care about? In a society obsessed with celebrity worship and showbiz, the answer is clearly a resounding yes. But the problem isn’t that famous people shouldn’t speak out about politics or social issues. The problems begin when celebrities try to speak for the people they are trying to help. This is especially true when they don’t actually belong to the group they claim to represent.

Every citizen should have the right to publicly take up issues of social welfare, injustice and matters of war and peace. The average Joe doesn’t have the time or the resources to devote to such causes, however, whereas millionaire celebrities have plenty of money and time on their hands. When a celebrity throws their political capital behind a movement much larger than themselves, the success or failure of that movement can become entwined with their personal reputation. The heavier the capital, the more inseparable they become from the cause in many cases.

Celebrities might have the noblest of intentions, but they can also end up having a negative effect on the issues if they aren’t careful.

John Lennon is one example of a celebrity who was able to successfully brand himself as a ‘peace activist’ by simply supporting the idea of peace without giving any definitive answers about how to actually achieve it or what it even meant. His reputation was enhanced among progressives and anti-war supporters, but his political opinions (naïve as they were) got him into hot water with the US Government, which was heavily invested in the Vietnam War at the time.

Traditionally, musicians have been at the forefront of activist causes, in the folk traditions of union organizers like Woody Guthrie, Joe Hill and Pete Seeger. More recent examples of musicians bringing awareness to social issues include George Harrison’s Concert for Bangladesh in 1971; Bruce Springsteen and a host of others with the NO NUKES concerts in the late seventies – right through to LIVE AID, FARM AID and the TIBET FREEDOM concerts in the eighties and nineties.

Pop stars like Bob Geldof, Willie Nelson, Neil Young, Chrissie Hynde, Dave Matthews, Bonnie Raitt, Paul McCartney, Erykah Badu and Bono from U2 have been high-profile champions of worthy causes. The LIVE AID concert on July 13, 1985, and the subsequent LIVE 8 shows in 2005 are two particularly notable examples of successful consciousness-raising regarding global sustainability issues – although they brought us no closer to any actual solutions.

Entertainers like the late Danny Thomas used to be a rarity. A true visionary in the field of celebrity activism, he helped establish St. Jude’s Hospital in Memphis, Tennessee in 1962. Thomas’s daughter Marlo and husband Phil Donahue still work to raise money for the internationally-recognized children’s health facility and non-profit Medical Corporation.

From the early 1950s until 2011, Jerry Lewis served as national chairman of the Muscular Dystrophy Association (MDA). He started hosting telethons to benefit MDA in 1952, and from 1966 until 2010 he hosted the annual Jerry Lewis MDA Telethon, now called the MDA Labor Day Telethon. In August of 2011 it was announced that Lewis would no longer host any further telethons due to his declining health.

Harry Belafonte, Sidney Poitier and others were instrumental in promoting civil rights legislation in the early ‘60’s; French actress Brigitte Bardot retired from movies in 1974 to devote all of her time to animal rights causes; Audrey Hepburn also supported animal rights, UNICEF and the United Nations.

Today, celebrity activists are a dime a dozen. Angelina Jolie is following in Hepburn’s footsteps. She has been an outspoken campaigner who volunteers her time and money to various causes. Jolie is a goodwill ambassador to the U.N. as a member of the Council on Foreign Relations, the international foreign policy think-tank.

Tennis legend Andre Agassi established the Andre Agassi Preparatory Academy, a charter school for at-risk kids in his hometown of Las Vegas, Nevada. Now considered one of the best prep schools in the country, Agassi and his wife, fellow tennis legend Steffi Graf have donated more than $35 million to the project so far.

Ben Affleck, Oprah Winfrey, Leonardo DiCaprio and Sean Penn are further examples of celebrities who have taken a public stand on important issues, and in some cases they’ve experienced career setbacks because of them.

Ashton Kutcher’s anti-sex slavery campaign is a recent example of celebrity activism gone wrong. He made his case with poor data which resulted in a public awareness campaign that wrongly identified the root cause of sexual slavery as essentially a moral issue, and in the end Kutcher trivialized and misinformed people about an important cause.

A celebrity is an asset only insofar as he or she is respected. If they don’t have that respect, they become a liability. Sometimes celebrities would do better to just write a check and shut the hell up.

Celebrity interest in Africa has become something of a cliché, thanks to Angelina Jolie’s adopted daughter and over-hyped events like Madonna’s adoption of a child from Malawi several years ago.

Thanks to his arrest for protesting outside the Sudanese embassy we can add George Clooney to the list. But as Sudanese writer Nesrine Malik pointed out in The Guardian, the US media’s preoccupation seemed not to be with the suffering of the Nuba mountain people – the cause Clooney is advocating for – but with fawning over the virtues of celebrity activism. Malik sarcastically referred to Clooney’s replies to the reporters as “beauty pageant contestant responses to what is actually going on in Sudan.”

To many people, celebrities like George Clooney come off as well-meaning, but ultimately irresponsible and even potentially destructive to the cause. The problem with Clooney’s selective approach to humanitarianism is that it implicitly perpetuates the idea that genocidal acts are carried out by other governments – never by our own.

Most of us are still unwilling to accept that the economic policies of our own government are responsible for most of the world’s suffering. That certainly goes for clueless celebrities.

George Clooney should be commended for his efforts to bring awareness to the plight of the people he claims to support, but he also needs to be careful when he tries to over-simplify matters for the general public, and he needs to consider that his humanitarian work might appear to be self-serving to some people. It’s a fine line to be sure.