Actor Leonardo Dicaprio has decided not to campaign for any of the 2008 U.S. presidential candidates, because none of the politicians in the running "inspire" him. The Blood Diamond star, 32, was a staunch advocate of Democratic hopeful Senator John Kerry during 2004's presidential election and even travelled across 14 states to rally support and raise funds for him. But DiCaprio admits the frontrunners for 2008's election - Democratic candidates Senator Hillary Clinton and Barack Obama and Republican Ron Paul - have yet to catch his attention with their environmental policies. He says, "I'm still on the fence about it, to tell you the truth. I have yet to hear a candidate that has clearly laid out their environmental policy in a way that is inspiring to me." Referring to Senator Kerry's previous election campaign, DiCaprio adds, "I thought he had an amazing environmental policy. But I have yet to hear a candidate that has compared in that regard. "I'm waiting for the right questions to be asked, and for these candidates to give really clear responses to what they're going to do in a tangible way - not a lot of rhetoric. I want to hear hardcore facts."