Former US vice president Joe Biden speaks during his first campaign event as a candidate for US President at Teamsters Local 249 in Pittsburgh, Pennsylvania, April 29, 2019. Saul Loeb | AFP | Getty Images

Former Vice President Joe Biden gained steam among Democratic voters in his first week as a declared candidate for president, putting more distance between himself and the crowded field of primary candidates already in the running. Three national polls published Tuesday show that Biden, who was already the early front-runner, gained substantial ground after formally joining the Democratic presidential primary contest last week after months of hesitation. Biden centered the launch of his campaign on his ability to defeat President Donald Trump, particularly in Rust Belt states like Michigan and Pennsylvania. He has earned more attention from the president, who dubbed him "Sleepy Joe," than his Democratic fellow contenders.

Biden, a longtime former senator from Delaware, gained 11 percentage points in April, according to a poll conducted by SSRS for CNN last week. Another survey, conducted by Morning Consult, shows Biden gained 6 percentage points since a week before. Both show that Biden is leading Sen. Bernie Sanders, his nearest competitor, by double digits. Biden is the favorite of 39% of Democrats or Democratic-leaning independents according to the CNN poll and of 36% of registered voters likely to vote in the primary, according to Morning Consult. In the same polls, Sanders holds 15% and 22%, respectively. And a third poll, conducted by Quinnipiac University, found Biden had even more support, with 38% of Democrats favoring him. Sen. Elizabeth Warren came in second at 12% in that poll, and Sanders took 11%. South Bend, Indiana, Mayor Pete Buttigieg, Sen. Kamala Harris and former Texas Rep. Beto O'Rourke are the only other candidates with 5% support or greater. Of course, things could change. With nearly a year before the first primary contest, a majority of Democrats consistently tell pollsters that they have not finalized their choice. Historically, though, early polling does provide some insight into the likely primary victor.

Inside the numbers

Notably, Biden's lead stretches into states where Sanders has structural advantages. A poll conducted by Suffolk University and The Boston Globe, released Tuesday, showed that Biden leads Sanders in New Hampshire by 8 percentage points. Sanders, a popular longtime senator for Vermont, prevailed by more than 20 percentage points in the Granite State's 2016 primary contest against Democratic rival Hillary Clinton. The CNN and Morning Consult surveys show that Biden also holds a commanding lead among nonwhite voters, a demographic that could be key to the fortunes of the Democratic primary field.

Half of nonwhite voters told CNN that Biden was their top choice for the Democratic nomination. In comparison, Sanders received the support of only 14% of nonwhite voters. Warren received 7% of nonwhite voter support, while Harris and O'Rourke tied for 4%. Biden also leads black voters according to Morning Consult, with 43% support compared with Sanders' 20%. In the Morning Consult survey, Harris was the favorite of a tenth of black voters, Warren picked up the support of 6% and Sen. Cory Booker received 5%.

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