Andrew Gillum greets Stacey Abrams before a panel discussion last year. Both were unabashedly progressive in their 2018 gubernatorial campaigns. (Michael Robinson Chavez/The Washington Post)

Stacey Abrams and Andrew Gillum represent case studies in the new politics of America and give voice to a discussion inside the Democratic Party about how to win the presidency in 2020. The questions are these: What kind of candidate and what kind of campaign would give Democrats the best chance to defeat President Trump?

Abrams fell about 55,000 votes short of winning the governorship of Georgia, but she got more votes than any previous Democrat in the state. Gillum came within about 33,000 votes — less than half a percentage point — of winning the governorship of Florida, the best showing for a Democratic gubernatorial candidate there in two decades.

Abrams would have become the first African American female governor in the history of the country. Gillum would have become the first African American governor in Florida’s history. Both ran as unapologetic progressives, focusing on communities of color, on LGBTQ rights and on issues important to core constituencies. Gillum advocated higher corporate taxes and was a supporter of Medicare-for-all.

Would a more moderate candidate have done better in either case? Would a white candidate have done better? Would a white male candidate have done better? As the most diverse field of presidential candidates in the party’s history continues to expand this weekend, such questions will be an important part of the calculus for Democratic voters as they choose a nominee.

The country already has elected an African American as president, but Barack Obama’s victories notwithstanding, the issue of race remains foremost in politics in the Trump era. Gillum recalls a moment early in his campaign when the race question was posed directly by a woman attending one of his events at The Villages, a nearly all-white community in Florida. “She said, ‘Do you think Florida is going to elect a black man?’ ” Gillum said in an interview a few days ago.

Gillum knew many voters were wrestling with that question, particularly Democrats as they were sizing up their potential nominees. “I thought, ‘Thank God that we’re not going to let the question of race sort of sit silent in people’s heads waiting around, where their unconscious bias is made,’ ” he said.

Abrams, who delivered the Democratic response to Trump’s State of the Union address Tuesday, addressed some of these questions in a recent essay in the publication Foreign Affairs, responding to an article by Francis Fukuyama decrying identity politics.

Fukuyama argued that Democrats should focus on broader economic issues as a way to win back some white Trump voters, rather than making direct appeals to individual constituencies that make up the party’s coalition — African Americans, Hispanics, members of the LGBTQ community, professional women and others.

Abrams disagreed. “What Fukuyama laments as ‘fracturing’ is in reality the result of marginalized groups finally overcoming centuries-long efforts to erase them from the American polity — activism that will strengthen democratic rule, not threaten it,” Abrams wrote.

She pointed to the 2018 election, which produced the most diverse class of Democratic House members in history, as evidence that identity politics can be a successful strategy. Abrams said that, in her own campaign, she “intentionally and vigorously highlighted communities of color and other marginalized groups,” while not ignoring other voters. “I refused to accept the notion that the voters most affected by these policies would invariably support me simply because I was a member of a minority group,” she wrote.

Both the Georgia and Florida campaigns were marred by racial controversies, from voter suppression in Georgia to a racially charged statement from Gillum’s opponent, now-Gov. Ron DeSantis and later under-the-radar racial attacks. Gillum said the issue of race became toxic in the general election. In one of the debates, Gillum said of his opponent, “I’m not calling Mr. DeSantis a racist. I’m simply saying the racists believe he’s a racist.”

Turnout in Florida topped 8 million votes, far higher than in the 2014 gubernatorial race. Gillum’s candidacy, like Abrams’s in Georgia, energized Democratic base voters, and they turned out in big numbers. Republicans responded in kind, and the president’s popularity in Florida — and the time he invested in the gubernatorial race — produced a counterforce Gillum says was a significant factor in his loss.

“I think that came at a cost, certainly in the general [election],” he said of the toxicity of the race issue. “I didn’t think it at the moment. I do think that it came at a cost because I think it pushed people to the sides.”

Abrams’s State of the Union response underscored her beliefs that progressive ideas and a progressive message can be a winning strategy for a Democratic candidate. Gillum agreed. He said he resisted suggestions from some advisers to moderate his message during the campaign and recalled a difficult conversation with a leader of a black church who was concerned about Gillum’s strong support for marriage equality and LGBTQ rights.

Gillum does not believe a white candidate would have fared better in the gubernatorial race. “I would say the numbers don’t support that me being progressive, and my race, caused me to do worse than more conservative candidates who have run in my state,” he said.

He said what cost him most was the superiority of the Republican voter mobilization effort. Republicans, he said, are still better than Democrats at turning out voters in Florida. “They get that their voters don’t need a rally,” he said. “They don’t need a parade. It is muscle memory practically.” That’s a warning for the 2020 Democratic nominee.

The replays of the 2016 campaign will be in the background of the 2020 Democratic nomination contest. Did Hillary Clinton lose to Trump because she didn’t find a way to win more white voters in the industrial states and the upper Midwest? Or did she lose because she wasn’t able to motivate and mobilize more African Americans in states where she narrowly lost?

Gillum has been talking with some of those who will seek his party’s nomination in 2020 and has some advice. The first is not to trim their sails on progressive issues but to make them part of a more aspirational message. “I really think that our nominee should, to the best of our ability, try to cast a bigger, more hopeful vision,” he said.

Second, he said, the Democrats must not assume Trump voters are permanently lost to them. Some of those voters, he said, are gone, particularly those who see things through a racial lens. But there are others in the Trump coalition who were drawn to the president for other reasons. Democrats. he said, should compete for those voters and not try to invalidate the emotions and perceptions that made Trump an attractive candidate to them.

Finally, he said, “Do not chase him [Trump] down a rabbit hole. At every opportunity please go back to what you think we have in common.”

This is a lesson that has become clearer to Gillum over time. “If I had it to do [again], I probably would have ignored him more,” he said. “I don’t think I’ve made that admission before. But I think I probably would have ignored him. . . . But it’s hard when you know the president the United States is coming after you.”