(CNN)– Celebrity endorsements and star power have had substantially different and sometime adverse effects on presidential candidates. Oprah Winfrey, Halle Berry, Zack Braff and Scarlett Johansen have thrown their support behind Barack Obama helping to raise millions of dollars for his White House run, but superstar George Clooney is hesitant to go out and campaign for Obama calling it a ‘slippery slope.’
“I feel that at times you can harm the person that you are trying to help,” Clooney told CNN’s Kiran Chetry in reference to campaigning for Obama. “I don’t want to damage anybody.”
A few months ago, talk show host Oprah Winfrey was criticized by some of her fans for breaking her track record or staying out of politics. The media mogul spent a weekend campaigning with Barack Obama in South Carolina, Iowa, and New Hampshire.
Star power has helped bring attention to crises on the international spectrum. Clooney, who was recently named the United Nations' peace messenger, has used his influence to focus efforts on the crisis in Darfur and Sudan. He says candidates will always go to Hollywood because of the money that is there and the camera crews that are sure to follow.
The Academy Award winning actor officially endorsed Obama early last year calling him a ‘rock star.’ Clooney compared him to the likes of John and Robert Kennedy saying, “Few people in my lifetime, that I’ve heard speak made me want to get up and do something,” but cautions, “I don’t want to hurt him by saying that.”
Related: Watch Kiran Chetry's one-on-one with George Clooney
– CNN’s Emily Sherman