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 traveled 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.