NATIONWIDE — Almost two dozen Democratic presidential candidates will take the stage over the next two nights for the second round of debates of the 2020 campaign.

• 2nd round of Democratic presidential debates begins tonight
• It could be last debate appearance for lower-polling candidates
• DECISION 2020: Decision 2020 special coverage | Politics headlines | Spectrum News DC Bureau coverage | Untangled with Josh Robin

This time, the debates are being held in Detroit, in a state President Donald Trump narrowly won in becoming president in 2016. Each debate will begin at 8 p.m. ET and be broadcast by CNN.

The Detroit debates are another chance for the candidates to detail their visions and try to stand out in a crowded field before a national television audience.

Some of the higher-polling candidates hope to close the gap between themselves and former Vice President Joe Biden, who is leading in polls. The debates may also be the last chance for some of the lower-polling candidates to make their mark.

What's different about these debates?

Nineteen of the 20 candidates who took part in the first debate will participate in one of this week's debates. The lone newcomer is Montana Gov. Steve Bullock, who replaces California Rep. Eric Swalwell. (Swalwell dropped out of the race earlier this month.)

Candidates qualified for this debate in one of two ways:

1. Registering 1 percent or more in at least three qualified polls. These include national polls, or polls conducted in Iowa, New Hampshire, South Carolina or Nevada.
   
   
2. Receiving donations from at least 65,000 unique donors, and by receiving donations from a least 200 unique donors per state in at least 20 states.

As they were in Miami last month for the first debate, the 20 candidates will be split into two groups of 10 and will debate on two separate days.

Tuesday debate participants

Wednesday debate participants

Former Alaska Sen. Mike Gravel, Miramar (Fla.) Mayor Wayne Messam, Massachusetts Rep. Seth Moulton, former Pennsylvania Rep. Joe Sestak, and activist Tom Steyer are the Democratic candidates who are not participating.

How did the race change after the 1st debate?

Judging by RealClearPolitics polling data, the first debate was very significant for California Sen. Kamala Harris, who enjoyed a bump in popularity after criticizing Biden for defending working with segregationists, and for once opposing mandatory busing of students to desegregate public schools.

According to RealClearPolitics, her average in all polls surged from 7 percent on June 29 to 15.2 percent by July 5. A lot of her gain came at the expense of Biden, who dropped from a 32 percent polling average on June 29 to a 26 percent polling average on July 6.

Biden has gained back some ground since then. As of this week, his RealClearPolitics polling average was at 29.3 percent. Despite the setback, Biden is still 14.3 percentage points ahead of his nearest challengers, Sens. Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts. Sanders is polling at 15 percent, and Warren is polling at 14.5 percent. Harris is currently at 11.8 percent.

What should we expect from the 2nd debate?

In the first debate, candidates tangled on immigration, taxes, health care, and civil rights, among other topics. Expect the second debate to include conversations about these topics again, and potentially more questions about trade and cities.

Candidates could take the opportunity to criticize the private detention centers where immigrants are being held at the border, as many did during the first debates.

Health care — specifically, the topic of whether to abolish private insurance — was brought up at both debates during the first round, and may come up again as the candidates try to make distinctions between their plans. (Warren, Harris, Sanders, and New York City Mayor Bill de Blasio all said they would abolish private insurance during the first debate.) Sanders and Warren, who are the Day 1 candidates with the highest rankings in the polls, may end up taking the heat from their rivals in that debate.

Biden still appears to be the front-runner, so he could again be the focus of attacks from other candidates on Day 2, particularly from Harris, Sen. Cory Booker, and de Blasio, who have publicly criticized Biden in the past. Harris may also face more attacks than she did in the last debate after rising in the polls. 

Trump is expected to be a topic of discussion as well. Candidates may use their time to further denounce his tweets suggesting that four Democratic congresswomen should "go back" to the "broken and crime infested places from which they came," comments that were officially condemned by the House, and to discuss racial relations overall in the country.

Former special counsel Robert Mueller's investigation into Russian interference in the U.S. elections process, and Trump's response to the investigation, may also be discussed after Mueller's testimony in House hearings last week.

Trump himself may use Twitter to weigh in during the debates, as he did during the first round.

What the next round of debates means for Florida?

In the last debates that took place in Miami, Booker mentioned the opioid crisis impacting many states, such as Florida. He said that drug companies that make the drugs should be held criminally responsible for causing the crisis.

The New Jersey senator said he wants to see those companies pay for "solutions that are working," however, he did not mention what those solutions would be. 

With many Floridians and Americans still suffering from the opioid crisis, the topic is expected to come up again.

Another big health-related topic that was discussed and is sure to be a continued conversation will be health care reform. Sanders was adamant about passing the Medicare For All single-payer system, saying that the vast majority of people would pay less than they are now for healthcare.

However, he danced around the topic of how that would be paid until he finally admitted that he would raise taxes for the middle class. He said the middle class would be paying more in taxes but less in healthcare for what they will be getting.

Only a few of the Democratic candidates, Sanders included, stated they would abolish private health insurance and go with a government-run universal health care system.

The majority of the candidates said that they would not eliminate private health insurance for people who want to keep their coverage, but some of them had their own ideas on how they would tackle health care, with Biden saying he would build on what Affordable Health Care Act, or "Obamacare," did.

Another topic that has made the news again in recent weeks is what is happening in Puerto Rico. During the last debate in June, one of the main concerns was the delay in funding for both the Florida Panhandle and the American territory after the devastating impact of Hurricane Michael.  

The $19-billion disaster relief package included money for Puerto Rico, as it continued to recover. 

However, in recent weeks, Puerto Rico has been thrust into the national spotlight again after it was discovered that Gov. Ricardo Rosselló allegedly sent out profanity-laced, crude messages between himself and 11 top aides and Cabinet members. He announced last week that he will resign.

The new problem is that there is currently no successor to become the next governor. Secretary of Justice Wanda Vazquez has refused to accept the position, even though she is next in line.

The next person in line would be Francisco Pares Alicea, the Secretary of Treasury. However, there is a little problem: At 31 years old, he does not meet the age requirement of 35 to become governor. 

That means Puerto Rico's future is currently left uncertain and it leaves Puerto Ricans in Florida wondering what will come next.

Last debate for several candidates?

The rules for the first and second Democratic debates meant that 20 candidates qualified. But the rules for the third debate in September will make it harder for some of the lower-polling candidates to make it onto the debate stage.

The polling and fundraising thresholds will be higher for the third Democratic debate, and candidates will have to meet both thresholds instead of just one. To qualify for the third debate, candidates must receive 2 percent or more in at least four qualified polls. They must also receive donations from at least 130,000 donors, and from 400 unique donors per state in at least 20 states.

As of July 12, according to FiveThirtyEight, only five candidates met both thresholds so far: Biden, Harris, Sanders, Warren, and South Bend Mayor Pete Buttigieg.

The deadline for the candidates to hit both thresholds is August 28, so the other candidates still have time to make up the difference. A strong performance in the second debate could go a long way toward helping them reach that goal.

Information from the Associated Press was used in this report.

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