SAN FRANCISCO  Proposition 19, which would have legalized marijuana in California, received more votes than the Republican nominee for governor, Meg Whitman.

It also received untold news coverage, bringing the debate a new level of legitimacy in the eyes of many supporters. And while it lost  with 46 percent of the vote  its showing at the polls was strong enough that those supporters are confidently planning to bring it back before voters in California, and perhaps other states, in 2012.

“We’re going to win,” said Aaron Houston, the executive director of Students for Sensible Drug Policy, a nonprofit group in Washington. “And we’re going to win a whole lot sooner than anybody thinks.”

But for all that heady talk, proponents of legalization still face a series of stiff challenges, including winning over older members of the electorate  who overwhelmingly rejected the measure  as well as wary elected officials from both political parties. And while most advocates say that Proposition 19 was a high-water mark for the movement, many admit that the road to legalization will also require new campaign ideas, more money and a tighter, more detailed message to overcome persistent cultural concerns about the drug.