“Now we’re back here in the Midwest, where I’m from. I’m so happy to see all of you,” Clinton, a Chicago native, said to cheers at a campaign rally late Saturday in this St Louis suburb.

Nevada’s presidential caucuses gave Clinton a big boost, powering her to a second straight win over Obama in the first Western contest of the 2008 calendar. She bested Obama among women, as she did in New Hampshire, and showed significant strength among Hispanic voters — an important and growing segment of the Democratic electorate in the mountain West and key states like California, Florida and New York.

But Obama won decisively among black voters, who could account for more than 50 percent of the voters in South Carolina’s primary next Saturday. And Nevada’s likely delegate count appeared to be almost evenly split between Clinton and Obama, indicating a protracted delegate battle yet to come. Clinton acknowledged the excruciatingly tight race before departing Nevada, calling her win “one step on a long journey.” The Nevada results still spelled trouble for Obama, whose stunning victory in the Iowa caucuses January 3 has begun to fade amid evidence of his vulnerability among important demographic groups, especially white, working-class Democrats and women.

He tried to remedy that problem in Nevada, holding economic roundtables with women voters and bringing in his popular wife, Michelle, to campaign with him. But women outnumbered men among caucus-goers, and a sizable majority went with Clinton. Obama is now under greater pressure to win South Carolina, while Clinton is mostly hoping to hold her own there. Both campaigns are also looking ahead to “mega Tuesday” February 5, when more than 20 states hold contests.

Polls in South Carolina have shown black voters shifting to Obama despite their longtime loyalty to the Clintons and particularly to Bill Clinton who was once nicknamed the first black president.

With her Nevada win, campaign officials say she will campaign hard this week in South Carolina and hope for a strong enough showing to pick up sizable number of the state’s delegates. Former Democratic National Committee chairman Don Fowler, a South Carolinian who recently endorsed Clinton, said he was optimistic.

“I think she’s doing very well,” Fowler said. “I’m confident with the kind of campaign we’re running next week we’re going to win.”