"Where Did You Get This Number?" is a podcast going inside the 2020 presidential campaigns, with analysis from CBS News campaign embeds, polls and other stories from the 2020 race. Subscribe today!

Senator Bernie Sanders of Vermont has the highest percentage of "strong supporters" among all the 2020 presidential candidates, according to our October CBS News Battleground Tracker poll.

And while former Vice President Joe Biden and Senator Elizabeth Warren have been jostling back and forth to lead the 2020 Democratic presidential field, and Mayor Pete Buttigieg of South Bend, Indiana, has been rising Iowa and New Hampshire, Sanders has seen almost no movement at all.

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On this week's episode of the "Where Did You Get This Number?" podcast, host Anthony Salvanto takes a brief detour into impeachment analysis with CBS News Radio White House correspondent Steven Portnoy before exploring Sanders' base of support and campaign strategy for the 2020 Democratic primaries.

Democrats are trying to make a case that President Trump should be charged with high crimes and misdemeanors concerning the withholding of military aid from Ukraine in exchange for an investigation of his political rival, Joe Biden, while Republicans argue that the president did not commit a crime because the Constitution gives him the responsibility to set foreign policy, including decisions about aid.

"And that's the argument that Republicans are making, that the people who are talking at these hearings and testifying about how unusual, how inappropriate, how disconcerting it all was — well, that's their opinion, but the president ultimately has the power under the Constitution," Portnoy said.

Back in the 2020 presidential race, Bernie Sanders' campaign has just set a record for surpassing four million donations sooner than any other presidential candidate in history.

CBS News 2020 campaign reporter Cara Korte has been on the road with the Sanders campaign for the past half a year. Amidst the rolled-up jeans and patterned high socks, an emotional relationship has developed between the senator and his supporters, according to Korte.

"They see him as an O.G. who's been talking about these progressive ideas for more than 30 years," said Korte, adding on that many of Sanders' town hall events are "kind of like group therapies."

During his town halls, Sanders will first ask the audience for any stories about struggling to pay off debt and bills or losing a job, before taking questions.

"And of course, that just makes you think about President Trump and the kind of stories that he would tell on the trail and his supporters would tell on the trail," Korte said.

Sanders also has a particular pattern of campaigning, clustering events in one of the early primary states before making a stop in one of the Super Tuesday states like California.

"In California alone, there are more delegates than those first four states [Iowa, New Hampshire, Nevada, South Carolina] combined," Korte said. "And I think when we look at those high rally numbers in Super Tuesday states, it shows that Sanders' campaign is really playing a long game here."

Subscribe to "Where Did You Get This Number?" and listen to the latest episode to learn more about respective political parties' impeachment inquiry strategies, Sanders' campaign's supporters and strategies, and more!

The podcast is available on Apple Podcasts, Google Play, Stitcher, Spotify, Art19, or wherever you get your podcasts.

Host: Anthony Salvanto, Director of Elections and Surveys at CBS News

Guest: CBS News 2020 Campaign Reporter Cara Korte

Production Team: Rachel Armany, Maeve Burke, Jake Rosen, Allen Peng

Twitter: @WDYGTN

Instagram: @getthisnumber