A resurgent Joe Biden rode a wave of momentum to win at least eight states on Super Tuesday and Bernie Sanders was leading in the biggest race in California, setting up a one-on-one battle for the Democratic presidential nomination.
In a surprisingly strong showing, Biden rolled to victories across the South, Midwest and New England on the biggest day of voting in the Democratic campaign. Americans in 14 states cast ballots for a challenger to Republican President Donald Trump in the Nov. 3 election.
"For those who have been knocked down, counted out, left behind, this is your campaign," said Biden, the former vice president who had performed poorly in the first three nominating contests but broke through with a win in South Carolina.
"We are very much alive," he told roaring supporters in Los Angeles.
Sanders, the one-time front-runner who had hoped to take a big step toward the nomination on Tuesday, won Colorado, Utah and his home state of Vermont, Edison Research said.
Fox News and AP projected Sanders won California, whose 415 delegates represent the largest haul in the nominating contest. But Edison Research and other networks held off declaring a winner as results trickled in.
With overwhelming support from African American, moderate and older voters, Biden swept to wins in Alabama, Arkansas, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee and Virginia.
The second biggest prize Texas and Maine were too close to call. Sanders was slightly trailing Biden in Texas, a state he had heavily invested in and had hoped to win given its sizeable Latino population.
It was a spectacular turn of events for Biden, whose campaign was on life support after poor showings in Iowa and New Hampshire. Until a week ago he trailed Sanders in most state and national polls.
Biden's blowout win in South Carolina on Saturday provided a burst of new momentum, fuelling a wave of endorsements from elected Democratic officials and former presidential rivals including Pete Buttigieg, a former mayor, and U.S. Senator Amy Klobuchar of Minnesota before voting began on Super Tuesday.