The stage is prepped for a Democratic debate in April 2016 in Brooklyn. (Melina Mara/The Washington Post)

Democratic presidential candidates will meet in June for the first of at least 12 planned primary debates of the 2020 election cycle, under a plan released Thursday by party officials who said they were determined to create large debate audiences with broad candidate participation.

Entry to the early debate stages will be determined by a combination of polling, grass-roots financial support and other factors, in an effort to include candidates who are not registering nationally in public opinion surveys.

If the number of candidates is too large to host at a single event, the party plans to hold two events in the same location on consecutive nights, after randomly dividing the candidates in a public selection process. That would increase the number of actual debates beyond a dozen.

“Drawing lots strikes me as the fairest way to make sure everyone gets a fair shake,” Democratic National Committee Chairman Thomas Perez said Thursday. “We want our candidates to be able to articulate their vision of America. We don’t want debates to be discussions of what your hand size is. We want debates to be discussions of health care.”

As it did in the last presidential election, the Democratic Party will threaten to punish candidates who participate in debates outside of the official schedule. But candidates are welcome to attend forums or town halls with their competitors, as long as they appear in sequence and do not directly engage with each other before voters.

Democratic officials have been meeting for months with media partners and veterans of the last campaign to create the debate plan, with the goal of avoiding the controversy that defined the last debate process.

How would you narrow the 2020 Democratic field?

The 2016 debate plan was drafted in close consultation with advisers to Hillary Clinton, but not her rivals. It started the debates in mid-October 2015, allowed only three debates before the new year and scheduled the debates at times when they were less likely to be watched. Clinton’s two primary rivals, Sen. Bernie Sanders (I-Vt.) and former Maryland Gov. Martin O’Malley, both claimed the process had been rigged in her favor.

In total, Clinton debated her Democratic rivals nine times over the course of seven months. An analysis by NDN, a Democratic think tank, found television viewership of the 12 Republican primary debates in 2016 was about 186 million, more than double the 72 million people who tuned in for the Democratic debates.

This time, Democrats will host at least six debates in 2019, all of them in states that do not hold early primary or caucus contests. There will be at least six more debates in early 2020, including meetings in Iowa, New Hampshire, Nevada and South Carolina.

The first two debates will be held in June and July. After an August break, they will continue on a monthly basis through the rest of the year. The last debate in 2020 is now scheduled for April.

The debate reforms are part of a larger effort by Perez to make the Democratic nomination process more transparent and maximize the involvement of voters. Up to this point, Democratic officials have not consulted with prospective 2020 candidates or their staffs on the debate planning, unless those people were involved in the 2016 primary campaign.

“Even the perception of impartiality or an unfair advantage undermines our ability to win,” Perez wrote to fellow members of the party in November of 2017.

Since then, the Democratic National Committee has reduced the voting power of party officials, known as “superdelegates,” while encouraging states to hold primaries instead of caucuses, which tend to get less people involved. State parties holding caucuses will be required to accept absentee votes in 2020.

“Our north star principles are clear: making sure every candidate gets a fair shake and making sure voters across the country have an ample opportunity to get to know our nominees,” Perez said.

The exact qualifications for making the debate stage will be announced in January. The dates, locations and media partners for the events will also be released early next year.

For lesser-known candidates, the debates are a crucial moment to showcase their qualifications, and several candidates are likely to lobby the committee in the coming weeks to make sure they can be included in the cutoff for the first debate.

“I’d also like to see online engagement factored in, embracing the way that people engage with politics in the 21st century,” said Rep. Eric Swalwell (D-Calif.), who has been edging toward his own presidential campaign. “Polling has been off in the last few years, as we’ve seen. When you have a lot of qualified, talented candidates running there’s no avoiding a big dinner table.”

Several potential candidates and their advisers responded positively to the Perez plan.

“My first piece of advice was not to have one campaign set up the schedule, then send it out like it’s the DNC’s own,” said Jeff Weaver, Bernie Sanders’s campaign manager in 2016, who met with Democratic officials as they were drafting the proposal. “That’s not happening now.”

Pete Buttigieg, the South Bend, Ind., mayor who is considering his own presidential campaign, said the party had gone out of its way “to make sure it’s a fair process this time.”

Others agreed. “It feels like a reasonable approach,” said Rep. John Delaney (D-Md.), who entered the race more than a year ago but has polled far behind better-known candidates.

David Weigel in Des Moines contributed to this report.