WASHINGTON — Sen. John McCain seized command of the race for the Republican presidential nomination Tuesday night, winning delegate-rich primaries in all regions of the country. Democratic rivals Hillary Rodham Clinton and Barack Obama traded victories in an epic coast-to-coast struggle with no end in sight.

Clinton won the biggest state, California, for the Democrats, capitalizing on support from Hispanic voters.

McCain led the Republican race in the Golden State, hoping to inflict a crushing blow on his closest pursuer, former Massachusetts Gov. Mitt Romney.

"We've won some of the biggest states in the country," McCain told cheering supporters at a rally in Phoenix after pocketing victories in all regions. An underdog for months, he proclaimed himself the front-runner at last, and added. "I don't really mind it one bit."

With 497 delegates, the Arizona senator was more than 40 percent of the way to the 1,191 needed for the nomination — and far ahead of his rivals in that competition that counted most.

Even so, Mike Huckabee and Mitt Romney said they were staying in the race.

Neither Clinton nor Obama proclaimed overall victory on a Super Tuesday that sprawled across 23 states, and with good reason.

"I look forward to continuing our campaign and our debate about how to leave this country better off for the next generation," said the former first lady, looking ahead to the primaries and caucuses yet to come.

Obama was in Chicago, where he told a noisy election night rally, "Our time has come. Our movement is real. And change is coming to America."

McCain, the early Republican front-runner whose campaign nearly unraveled six months ago, won in New York, New Jersey, Connecticut, Missouri, Delaware and his home state of Arizona — each of them winner-take-all primaries.

Huckabee, the former governor of Arkansas, won a series of Bible Belt victories, in Alabama, Georgia and Tennessee as well as his own home state. He also triumphed at the Republican West Virginia convention, and told The Associated Press in an interview he would campaign on. "The one way you can't win a race is to quit it, and until somebody beats me, I'm going to answer the bell for every round of this fight," he said.

Romney, the former governor of Massachusetts, won a home state victory. He also took Utah, where fellow Mormons supported his candidacy. His superior organization produced caucus victories in North Dakota, Montana, Minnesota and Colorado, and he, too, breathed defiance. "We're going to go all the way to the convention. We're going to win this thing," he told supporters in Boston.