Sen. Bernie Sanders' 2020 presidential campaign is being taken much more seriously by well-connected officials of past Democratic campaigns, according to a report by Politico. 

Polls are consistently showing the Vermont senator and 2016 Democratic primary runner-up as either leading or near the top of the crowded field nationwide and in the individual contest.

“I believe people should take him very seriously. He has a very good shot of winning Iowa, a very good shot of winning New Hampshire, and other than Joe Biden, the best shot of winning Nevada,” Dan Pfeiffer, who served as an adviser to former President Barack Obama, said to Politico. “He could build a real head of steam heading into South Carolina and Super Tuesday.”

The report marks a very serious change in tone regarding the Sanders campaign, with many former officials believing Sanders would be unable to persuade voters outside of what was seen as a "narrow and far-left base." 

But after suffering a heart attack and numerous attacks from his competitors, the self-described Democratic socialist has remained a top contender in the race.

“Democratic voters like him, and if he starts winning, there could be a bandwagon effect,” GOP pollster Frank Luntz, who conducted a California focus group that found most participants thought Sanders had won the December Democratic debate, was quoted as saying in the piece. “I think you’re going to see continued movement. Sanders has been gaining in California over the past two months.”

With the growing support and change in tone from many established party figures, Larry Cohen, chairman of the pro-Sanders group Our Revolution, believes the secret to winning the nomination could be in gaining support from fellow progressives who are currently behind Sen. Elizabeth Warren. 

“The math is that if you think of the voters for Warren and the voters for Sanders as two circles, yes, there is overlap, [but] most of the circles are separate,” Cohen said. “I think between them, we can get to a majority.”

Despite the new projections, no votes have been cast in the 2020 race, and no official numbers will be known until the Iowa caucuses February 3, 2020.