The TIME 100

In an era when Republicans across the nation seem intent on tearing the "conserve" out of conservatism, California Governor Arnold Schwarzenegger, 59, is a national leader for his efforts to restore Teddy Roosevelt's conservation tradition to the G.O.P.

When he took office in 2003, Schwarzenegger announced a bold action plan for improving the state's air, water, landscapes, energy supplies and climate. He created the 25 million-acre Sierra Nevada Conservancy to preserve California's iconic mountain range; established thousands of acres of ocean parks; and put millions of dollars into habitat restoration, fisheries management and pollution reduction. He also adopted the most aggressive greenhouse-gas-reduction policies on earth, including ordering the state government to slash its energy use 20% and providing $3.2 billion to put solar roofs on homes and small businesses. By 2020 one-third of California's electricity will come from renewable sources like wind, biomass and the sun. Schwarzenegger's commitment to green growth often pits him against his own political party. He has fought off the Bush Administration's efforts to weaken California's global-warming initiatives and drill for oil along the coast and in the state's national forests. A true fiscal conservative with a deep commitment to California's future, the Governor regards environmental injury as deficit spending—loading the cost of this generation's prosperity onto the backs of our children. Schwarzenegger believes that good economic policy, over the long term, is always the same as good environmental policy.

Kennedy, related to Schwarzenegger by marriage, is an environmental lawyer for NRDC and president of Waterkeeper Alliance