Democratic National Committee Chairman Tom Perez said Thursday that the DNC will host 12 debates for the 2020 Democratic primaries, with six held in 2019 and six held in 2020. Democrats are expecting a crowded field in the primaries, as several prominent politicians have expressed interest in a presidential bid.

The preliminary debate schedule and rules signal that Perez is trying to learn from past mistakes made by the DNC in organizing debates and ensuring fairness in the primary.

Perez, who spoke to reporters in a conference call Thursday, said that there will be no debates in states which hold early primaries in 2019, in order to prevent the candidates from focusing too much on early-voting states like Iowa and New Hampshire.

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"We want to make that voters in every state hear directly from candidates. That's why no early state debate will be held until 2020," Perez said. The first debate is expected to take place in June or July 2019, and the last debate in April 2020, when the field of candidates will be winnowed down.

Perez also emphasized the DNC's commitment to creating a "level playing field" with the debates. The committee was widely criticized in 2016 for supporting Hillary Clinton over Bernie Sanders during the Democratic primary, before Clinton officially clinched the nomination.

"Depending on the number of candidates who meet the threshold in first debate – I should say the first two debates – we will if necessary split those debates into consecutive nights and the participating candidates will be chosen by random selection and this random selection will take place publicly," Perez said.

The RNC was also criticized in 2016 for splitting its debates between the leading candidates and the undercard candidates, creating the appearance of a debate for real candidates and a "kiddie table" debate for those who were polling poorly. The Democratic field in 2020 may have even more candidates than the 17 Republicans in 2016.

Perez also said that decisions about who is allowed in a debate will not be dependent solely on meeting a polling threshold, like in previous years, but will take other factors into account, such as grassroots fundraising. Sanders made waves in 2016 for his ability to fundraise off of small dollar donations.

Jack Turman contributed to this report