After Biden victories, Sanders will stay in the race

(SOUNDBITE) (ENGLISH) SEN. BERNIE SANDERS, SAYING:

"Last night, obviously, was not a good night for our campaign..."

Despite another bruising night of primary losses, Senator Bernie Sanders on Wednesday said he's staying in the race.

(SOUNDBITE) (ENGLISH) SEN. BERNIE SANDERS, SAYING:

"I very much look forward to the debate in Arizona..."

Former Vice President Joe Biden was quickly declared the winner in Tuesday's nominating contests in Michigan, Missouri, Mississippi and Idaho on Tuesday, giving him perhaps unstoppable momentum toward winning the Democratic nomination to challenge President Trump in November.

Sanders, who won in North Dakota and is leading in Washington state, acknowledged that while he was losing in votes, he said polls show his ideas were winning over voters.

(SOUNDBITE) (ENGLISH) SEN. BERNIE SANDERS, SAYING:

"A strong majority of the American people support our progressive agenda... While our campaign has won the ideological debate, we are losing the debate over electability."

While Sanders had boasted that he could persuade more young voters and working class voters to show up at the polls, it's actually been Biden who has seen a wave of new support from suburbanites, particularly women.

In Michigan, Biden held about a 20-point advantage with all women, and he continues to dominate among African-Americans. And Biden's strength among suburbanites could be good news in the general election, as suburban voters were key to Democrats taking back the House in 2018.

The young voters who were supposed to fuel Sanders' revolution didn't turn out as expected. Voters under 29 made up just 14% of the Democratic primary electorate in Missouri and 16% in Michigan, lower percentages than in 2016.

Still on Wednesday, Sanders warned that any Democratic nominee can't ignore young voters.

(SOUNDBITE) (ENGLISH) SEN. BERNIE SANDERS, SAYING:

"You need to win the voters who represent the future of our country and you must speak to the issues of concern to them. You cannot simply be satisfied by winning the votes of people who are older."

Biden on Tuesday sure sounded like the presumptive nominee, thanking Sanders and his supporters in an appeal to unify the party.

(SOUNDBITE) (ENGLISH) DEMOCRATIC PRESIDENTIAL CANDIDATE JOE BIDEN, SAYING:

We share a common goal, and together we'll defeat Donald Trump. We'll defeat him together. We're going to bring this nation together."

The two men will face each other for the first one-on-one debate this Sunday.