The surge in support for Biden’s candidacy comes on the heels of big wins in South Carolina and most Super Tuesday states.

He was also the chief beneficiary of exits by three other contenders for the nomination — former New York City Mayor Michael Bloomberg, Sen. Amy Klobuchar (D-Minn.) and South Bend Mayor Pete Buttigieg of Indiana — who all endorsed him.

Democratic primary voters are starkly divided by age, with older voters overwhelmingly preferring Biden and younger voters — who have turned out to vote at much lower rates so far — siding with Sanders. Seventy percent of voters ages 45 and up are supporting Biden, compared with 57 percent of voters on the other side of that age divide backing Sanders.