Several states that caucused in 2016 will hold primaries instead in 2020, potentially dealing a blow to Sanders and other Democratic hopefuls with zealous followings.

“It’s absolutely going to make a difference in 2020,” said Robby Mook, Clinton’s 2016 campaign manager. “The caucuses tend to award the candidate who has the greatest intensity among a smaller group of supporters, rather than a candidate who has a broader base of support.”

Caucuses are seen as a boon for candidates with die-hard supporters because they can last for hours and require participants to vote out in the open. The beneficiaries are often candidates representing the ideological poles of each party, the most liberal Democrats or most conservative Republicans.