Democratic presidential hopeful former Vice President Joe Biden speaks during the fifth Democratic primary debate of the 2020 presidential campaign season co-hosted by MSNBC and The Washington Post at Tyler Perry Studios in Atlanta, Georgia on November 20, 2019.

The latest NBC News/Wall Street Journal poll shows Biden leading among Democratic voters with 28%, compared with 21% for Sen. Bernie Sanders, 18% for Sen. Elizabeth Warren and 9% for Mayor Pete Buttigieg. Sen. Amy Klobuchar and former New York Mayor Michael Bloomberg had 5% and 4%, respectively.

Former Vice President Joe Biden is holding his ground as the 2020 Democratic presidential front-runner with six weeks before the first nominating contest.

The process of selecting the Democratic nominee begins with the Iowa caucuses on Feb. 3. The New Hampshire primary, Nevada caucuses and South Carolina follow soon thereafter before 14 states hold contests on Super Tuesday, March 3.

Biden's resilience at the head of the pack has remained the constant in the Democratic race since he announced his candidacy last spring. Other candidates have seen their popularity fluctuate more, with Buttigieg creeping up into the upper ranks of the crowded field, Sanders fading and then regaining second place after his heart attack, and Warren losing ground after earlier challenging Biden for the lead.

The stability of Biden's standing has surprised political analysts who expected that mounting his third bid for the presidency at age 77, Biden would swiftly lose his edge. He faced heavy competition within a Democratic coalition now dominated by women, nonwhites and young voters.

But the new NBC/WSJ poll shows Biden holding 50% of the African American vote while Sen. Kamala Harris of California, once considered a strong African American challenger, has dropped out of the race. Biden leads Warren by 28% to 22% among Democratic women. He leads the 37-year-old Buttigieg among Democrats under 35 by 13% to 6%, even as the 78-year-old Sanders dominates that segment with 43%.

Yet the poll shows that trailing candidates still have openings to appeal to the hunger for change among Democratic partisans chafing at Donald Trump's presidency.