There are now roughly 100 days before the Iowa caucuses and the pace of the Democratic presidential race is picking up. In the past few weeks, Massachusetts Sen. Elizabeth Warren has been rising in the polls while Vermont Sen. Bernie Sanders has lost some ground.
While Sanders and Warren share a progressive position on many key issues, the two candidates are now beginning to highlight their differences.
During his 2016 presidential campaign, Sanders was the only candidate in the race promoting a progressive agenda — but this year, Warren poses serious competition for the primary voters who share these beliefs.
"I think that's what Bernie Sanders has to be very aware of: the fact is his lane of the Democratic Party is no longer just Bernie Sanders," said former NPR political director Ken Rudin, who is now the editor of the podcast Political Junkie. "The fact that she [Warren] has risen and he has probably remained stationary, if not lost a point or two, I think is significant."
So what are some of the key differences between Sanders and Warren? Sanders campaign senior adviser Jeff Weaver said Sanders is committed to leading a "political revolution" in this country, while he said Warren wants to merely fix the current political system.
"Bernie Sanders is really about fundamentally changing the power relations in this country," Weaver said. "It's not just about a few more regulations on some corporations. It's about fundamentally changing power relations so that we no longer have large corporations and the 1% running the country."
Middlebury College political science professor Matt Dickinson said the candidates themselves are starting to distinguish their differences by a using a framework of "socialism and capitalism."
"You've seen the two of them differ on word choice in recent weeks. ... For instance Warren, defending the capitalist system, saying she's a full-blooded capitalist," Dickinson said. "Whereas Sanders, he [is] using that as a point of distinction between the two of them."
Weaver said Sanders will also highlight the fact that he has fought for a progressive agenda his entire adult life.
"He fears no one and, you know, he doesn't back down," Weaver said. "So, you know one of the things I think people can know about Bernie Sanders is when he becomes president he'll fight for them because he always has."
Another key difference between Sanders and Warren, according to Rudin, is that Sanders has a tenuous link to the Democratic Party. Rudin said he thinks this could become a key issue in the coming weeks.
"When all is said and done, Elizabeth Warren is still a member of the Democratic Party. Bernie Sanders is not. Rudin said. "I mean, we know his history ... running as an independent and being elected as an independent, and so he is talking about a socialist revolution."
Last weekend, Sanders landed a key endorsement: Rep. Alexandria Ocasio-Cortez, in her first term in Congress, has become a leading voice in the progressive wing of the Democratic Party.
Ocasio-Cortez supported Sanders in 2016, and she threw her support to him at a huge rally Saturday in New York City.
Matt Dickinson, of Middlebury College, said he thinks this endorsement sends a strong message to progressive voters all across the country.
"I mean to have these people who have these huge social media following throw their support behind Bernie reflects a decision by the very progressive wing of the progressive wing that their view of Bernie is a more legitimate standard bearer," Dickinson said. "On the other hand, it's not clear how widespread Ocasio-Cortez or the Squad's support is within the party more broadly."
More from NPR — "Alexandria Ocasio-Cortez Says Bernie Sanders' Heart Attack Was A 'Gut Check' Moment" [Oct. 19]
And actually UVM political science professor Ellen Andersen thinks that this development could also benefit Warren. Andersen said Warren can use her failure to win the Ocasio-Cortez endorsement as way to appeal to more moderate voters.
"If she decides it makes sense to tack back towards the center," Andersen said, "there's a way that she could play this to say, 'Well look, you know, I'm really progressive — but I'm not all the way out there.'"
Politcal Junkie editor Rudin said there are also strong personality differences between Sanders and Warren: He described Warren as a "happy warrior" who spends hours taking selfies with her supporters, and Rudin contrasted this approach with Sanders, who he said often uses an impatient and sometimes angry demeanor at his rallies.
The next Democratic presidential candidate debate is scheduled for Nov. 20.
Correction 10/24/2019 10:59 a.m. An "and" was missing from one of Rudin's quote transcriptions. It has been updated.