WASHINGTON — The Democratic Party will hold its second presidential primary debate in Detroit on July 30 and 31, it announced Tuesday. 

CNN will host the second debate in Michigan, the key 2020 battleground where President Trump upset Democratic nominee Hillary Clinton in 2016. 

The criteria and format for the debate is virtually identical to the first round, which will be hosted by NBC, MSNBC and Telemundo on June 26 and 27 in Miami. 

Candidates can qualify through one of two routes—by reaching a polling threshold or amassing enough unique donations. 

To qualify with polling, a candidate must hit 1 percent or higher in three qualifying polls released between Jan. 1, 2019 and two weeks before the debate. Polls that meet the DNC's criteria include those conducted by: Associated Press, ABC News, CBS News, CNN, Des Moines Register, Fox News, Las Vegas Review Journal, Monmouth University, NBC News, New York Times, National Public Radio (NPR), Quinnipiac University, Reuters, University of New Hampshire, Wall Street Journal, USA Today, Washington Post, Winthrop University.

Polls can be either national polls or polls of Iowa, New Hampshire, South Carolina or Nevada. But in order to use two polls from the same organization, the polls must test different areas. 

The fundraising threshold for the debate is 65,000 unique donors and at least 200 unique donors per state in at least 20 states. 

The DNC is limiting the maximum number of candidates to 20, so it will give priority to candidates who meet both thresholds in the event that more than 20 candidates qualify.