The progressive lane in the 2020 Democratic field will be crowded, but there is a line being drawn, by the candidates themselves, between “progressive” and “socialist.” With Bernie Sanders’ recent decision to announce his candidacy, and double-down on his brand of “democratic socialism,” other candidates are being forced to pick sides over the “s” word on whether they want to embrace it during the 2020 Democratic primary.  President Trump has already made it a point to begin using the term “socialist” as a derogatory label against his 2020 rivals.

Believe it or not, the split in 2020 on the Democratic side may be happening due to the underlying push and pull from none other than Hillary Clinton, who has been working behind the scenes as an informal advisor to various candidates.

As The Hill reports, some Democrats have begun distancing themselves from the “socialist” label and instead pushing back on Bernie’s influence in 2020:

“I think socialist is a word that someone who wants to beat Trump should consider carefully before embracing,” said one senior adviser to a rival campaign.

It’s not a new argument. Hillary Clinton and her supporters offered a similar cautionary tale during their bruising 2016 primary fight against Sanders.

But it could have more resonance in 2020 as Democrats try to find the person who can defeat Trump after their devastating disappointment in 2016.

But this week, 2020 candidates — and those considering entering the race — have been actively drawing a distinction with Sanders and his brand.

At a campaign stop in New Hampshire earlier this week, Sen. Kamala Harris (D-Calif.) was the first to draw a line in the sand.

“The people of New Hampshire will tell me what’s required to compete in New Hampshire, but I will tell you I am not a democratic socialist,” Harris said after she was asked if she needed to be a democratic socialist to win the Granite State.

“I believe that what voters do want is they want to know that whoever is going to lead understands that in America today, not everyone has an equal opportunity and access to a path to success,” she said before adding that the U.S. needs to “course correct” on the issue of income inequality.

At the same time, former Rep. Beto O’Rourke (D-Texas), who is deciding whether or not he’ll run for president, also distanced himself from the label by declaring that he’s a “capitalist.”

“I don’t see how we’re able to meet any of the fundamental challenges that we have as a country without, in part, harnessing the power of the market,” O’Rourke told reporters in El Paso, Texas.

At a CNN town hall on Monday, Sen. Amy Klobuchar (Minn.), a centrist Democrat, made it known that she thinks Sanders’s policies are slightly unrealistic. When she was asked if she could get behind Medicare for all, she said, “It could be a possibility in the future.”

“I’m just looking for something that will work now,” she said, adding in a matter-of-fact way that she also was against free four-year college for all.

The notable names in this story are Kamala Harris and Amy Klobuchar, both of whom have been in private talks with Hillary Clinton regarding their 2020 aspirations.

The New York Times just put out a story today detailing Hillary’s involvement in 2020 and painting her as the “invisible” candidate in the primary:

In recent months, a parade of ambitious Democrats has held private sessions with Mrs. Clinton, who has counseled them about the unmatched rigors of the campaign trail and hardships of facing Mr. Trump, according to people familiar with the conversations. Beyond Mr. Biden and Ms. Klobuchar, she has spoken with Senator Kamala Harris of California; Mr. Booker; Senator Elizabeth Warren of Massachusetts; John Hickenlooper, the former governor of Colorado; and the former housing secretary Julián Castro, among others. She and Mr. McAuliffe speak regularly. Gov. Steve Bullock of Montana is trying to schedule a meeting with her.

“She knows almost everybody who’s running, and with most of the people she has a close relationship,” said Mr. Hickenlooper, who interviewed to be Mrs. Clinton’s running mate in 2016 and had dinner with her last year, as he prepared for a possible presidential bid. “You talk about divided affections. She’s got it.”

Not everyone has sought Mrs. Clinton’s advice. Senator Bernie Sanders of Vermont, whose 2016 primary challenge ruptured their relationship, has not spoken with Mrs. Clinton, or even reached out, despite the imperative to make inroads into her coalition.

Hillary put up a flailing fight against Bernie in 2016 and nearly lost the nomination to him due to her personal limitations as a communicator and the rabid passion among progressives seeking a candidate who would more strongly push the party further to the left.

If you think the feuding between Bernie and Hillary ended after 2016, you’d be wrong. There are many former Hillary staffers and advisors who feel that Bernie did a lot of damage to their candidate during the primary and ultimately gave Donald Trump some ammunition for the “cooked Hillary” line.

As a result, we see new stories out in the past few days containing some named and unnamed sources that are beginning to bash Bernie, and they all originate from the Clinton camp in some way.

Here’s an example recently from Politico where former Clinton staffers are lashing out at Bernie’s request for private air travel during the final months of the 2016 campaign while he spent time campaigning for Hillary:

But he also faces another hurdle: hard feelings that remain to this day after the contentious 2016 Democratic primary. Many in the party continue to believe the Vermont senator played a role in contributing to Clinton’s defeat in November because of his criticisms of her prior to the general election, and his refusal to concede earlier when it appeared he had little mathematical chance of securing the party nomination.

And they are eager to point out Sanders’ flaws and examples of what they perceive to be examples of hypocrisy now that the one-time underdog rates as one of the front-runners in the crowded Democratic field.

“I’m not shocked that while thousands of volunteers braved the heat and cold to knock on doors until their fingers bled in a desperate effort to stop Donald Trump, his Royal Majesty King Bernie Sanders would only deign to leave his plush D.C. office or his brand new second home on the lake if he was flown around on a cushy private jet like a billionaire master of the universe,” said Zac Petkanas, who was the director of rapid response for the Clinton campaign.

In 2016, after Sanders endorsed Clinton and agreed to campaign on her behalf, the Sanders campaign’s preferred mode of travel quickly emerged as a point of tension, according to six former Clinton campaign staffers and another source familiar with the travel.

Those who had worked on his primary campaign made it known that the only logistical way Sanders could adhere to the event schedules requested by the Clinton campaign was by flying private. The Clinton campaign, however, viewed the private jet flights as a needless extravagance and wanted the senator to mostly fly commercial.

The senator ended up flying private on three separate multi-day trips in the last two months of the campaign.

There is still bitterness between the Bernie and Hillary camps, and the division among the 2020 Democratic contenders will be another avenue for that to play out. Candidates like Kamala Harris, Amy Klobuchar, and Joe Biden, for example, will all be trying to play the middle ground in the primary without venturing too far toward Bernie’s politics.

This may be a result of their own strategizing trying to take away the “socialist” firepower from the Trump campaign, but it could also be a result of advice from Hillary on how to avoid alienating moderate voters who may not like Trump, but may be averse to far-left policies like free college and “Medicare for all.”

Some candidates, like Harris, have gone on the record to steer away from the “socialist” label entirely, according to RealClearPolitics:

Sen. Kamala Harris, a Democratic candidate for president in 2020, sets the record straight on her political philosophy, telling CNN’s John King in an interview that she is “not a socialist.”

“I certainly think that we should all want that our leaders do not engage in name-calling because that’s really just a very low-level of discourse,” Harris said. “I’m a progressive Democrat. I am a Democrat, I’m a proud Democrat. I’m not a socialist.”

Look for President Trump to insert the “socialist” label every chance he gets when referring to his Democratic rivals. This will result in the Democratic candidates being questioned about whether they consider their policies to be a form of socialism or whether they subscribe to Bernie’s democratic socialist mantle.

This will be a dividing line for the Democratic field and it’ll be interesting to watch as candidates basically pick their allegiance, either to the old guard of the party like the Clintons, or to the new, deeply-progressive strand being pushed by Democrats like Rep. Alexandria Ocasio-Cortez.