A progressive group is urging supporters of Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (D-Mass.) to back the other candidate in the Iowa caucuses on Monday should their preferred candidate not reach the required threshold to be counted.

THEY CAN DO THAT BY MAKING EACH OTHER THEIR SECOND CHOICE FOLLOWED BY THIRD AND FOURTH ETC. AS IT IS A PREFERENTIAL BALLOT 

Charles Chamberlain, chairman of Democracy for America (DFA), which has voiced support for both Sanders and Warren in the 2020 race, emphasized that Democrats should be united behind the progressive candidates heading into the caucuses.

“What we’re saying is if you’re a supporter of a candidate who gets less than 15 percent, then it’s absolutely critical that you don’t go home — make sure you move to one of the top two progressives, so that we make sure that a progressive wins the caucus," he said.

During the first round of the caucus, caucus goers walk around and stand in different areas indicating their support for a candidate. Candidates who fail to secure 15 percent of the total voters are removed and their supporters can then back another contender. 

“Making sure that we’re supportive of all of the progressives that are in this race and that we’re not attacking our own is really important because President Sanders or President Warren’s going to need Sen. Sanders or Sen. Warren to make sure to actually pass their agenda and that’s the best situation we could be in,” Chamberlain said.

DFA was among a number of progressive groups who signed a three-part unity pledge vowing to focus their fight on the “corporate wing” of the Democratic Party, ensure that a progressive candidate wins the party's presidential nomination and that they'd join forces to make sure the candidate they back defeats President Trump.

The move came after Sanders and Warren became embroiled in a bitter dispute earlier this month.

Though the two progressives had agreed not to attack one another, that comity broke down after reports that Sanders’s campaign was instructing volunteers to question whether Warren was electable.

Warren later alleged that Sanders told her in a private meeting in 2018 that a woman could not win the White House. Sanders, meanwhile, has denied ever making such a claim.

The spat culminated in an exchange following the Iowa debate. Warren confronted Sanders on the debate stage, and accused him of calling her a “liar on national TV.”

It is unclear whether the two candidates have spoken since, though Sanders’s campaign co-chair Rep. Ro Khanna (D-Calif.) came to Warren’s defense amid the public fallout and joined calls for unity.

“There are ups and downs in campaigns, but I have tremendous admiration and respect for Sen. Warren,” Rep. Ro Khanna (D-Calif.) told Hill.TV, noting Warren’s record on anti-corruption and founding of the Consumer Financial Protection Bureau.

Both progressive heavyweights have polled near the top of the Democratic field for most of the primary race, though Warren appears to have lost some momentum recently in state and national polls while Sanders has seen a surge going into the Iowa caucuses.

A New York Times/Siena College poll released on Sunday showed Sanders with 25 percent support followed by former South Bend, Ind., Mayor Pete Buttigieg at 18 percent, former Vice President Joe Biden at 17 percent and Warren at 15 percent.

However, other Iowa polls show Biden holding a narrow lead. According to a poll by Park Street Strategies, the former vice president garners 20 percent support and is trailed by Sanders with 18 percent. Warren and Buttigieg were tied at 17 percent each.

—Tess Bonn