LOS ANGELES (AP) – Mayor Villaraigosa of Los Angeles and Senator Clinton, Democrat of New York, kicked off a national volunteer drive Saturday to clean up litter and graffiti – an event that showcased environmental activism and presidential politics.

The 2008 campaign provided an obvious backdrop as the Democratic mayor showered Mrs. Clinton – the latest in a string of candidates to visit the state – with praise for her work on clean-energy, climate change and other programs in Washington.

“She’s been fighting for a brighter and cleaner future for all our children,” Mr. Villaraigosa said to cheers from a throng gathered around the City Hall steps. “She’s knows that our environment is not just the key to our health and happiness, she knows it’s the defining issue for our children’s future.”

Mr. Villaraigosa later indicated he didn’t have a favorite in the 2008 race, but the event gave the senator a chance to stand beside the popular mayor in a city with a large Democratic constituency as a dozen TV cameras rolled. The elaborately staged rally for the 2007 Great American Cleanup included dance troupes, an appearance by actress Daryl Hannah and a marching band.

As the state with the largest number of electoral votes and with its presidential primary expected to move to Feb. 5 from June, California has emerged as an important stopover for 2008 candidates. In recent days there have been visits from Senator Obama, Democrat of Illinois and former Senator Edwards, Democrat of North Carolina as well as former Mayor Giuliani and Sentor McCain of Arizona, both Republicans.

Without mentioning the presidential race, Mrs. Clinton said indirectly of the Bush administration that “our government has to get ahead of the climate-change issue. … We need people in Washington who understand that.”

“It’s time for us to take the subsidies away from the oil companies and put them to work for clean, alternative, renewable energy,” she said. “It’s time for us to get more mileage out of our cars.”