Democrats proved in 2008 and 2012 that they can win the presidency with energized African American voters. They actually won the popular vote again in 2016 without the obviously energizing figure of Barack Obama at the top of the ticket.
If Trump survives to run in 2020, voters will have four years of his bumbling, incoherent, incompetent presidency to look at, as opposed to 2016, when he was a political cipher. The results of the 2018 election, with Democrats resoundingly regaining control of the House of Representatives and failing to retake the Senate at least in part because they faced a very bad map, suggest that most voters are not very happy with two years of a Trump presidency.
White people in the United States are willing to accept more official racism than they ought, but they prefer their racism to be subtle. What Richard Nixon did brilliantly with his border south strategy — he chose not to compete with George Wallace for the overtly racist vote in the deep south — was to offer “the silent majority” as dog whistle racism that white people could see as implicitly critiquing African American civil rights protesters, as well as Vietnam War protesters, without being explicitly racist. Reagan and the elder George Bush both deployed similar tactics to win. George II did not win the popular vote in 2000, like Trump, and in 2004 had the psychologically gratifying substitute of same sex marriage to run against to appeal to voters who oppose civil rights in general.
Trump put Republicans in a bind by being very explicit in his racism. He chose Mexicans and Muslims instead of African Americans, but his roving prejudice could turn against African Americans very easily if need and opportunity require, in his twisted mind. In order to quash his candidacy, they would have had to alienate their base, whom they had cultivated since Nixon with the racist argument that that bad, old federal government only took money from hard working white people to give it to lazy black people. Since Republicans care about nothing but winning elections, they did not dare take that risk, even if it meant allowing an overt racist to win the presidency as a Republican.
Only eight percent of African Americans voted for Trump. They are the most loyal constituency of the Democratic Party, even though the Party has not done much for them since the 1965 Voting Rights Act. The real reason why Republicans hate the Affordable Care Act is that they realize it will benefit African Americans disproportionately because, as a class, they still fall out at the bottom of every metric of well being, including access to health care.
Anyone who still supports Trump at this point is hopeless. Democrats should waste no time or effort trying to appeal to Trump loyalists. They should articulate a robust program that will benefit all working class and poor people, which will necessarily help African Americans along with white people who fall into those classes. Democrats should get back to their New Deal roots. The Trump racists will not like it, but Democrats do not need their votes anyway. Adding the Democratic enthusiasm of 2018 to the popular vote win of 2016 means that Trump will have a very hard time winning in 2020, if he is eligible to run.
The Democrats should also specifically advocate policies that will benefit African Americans more specifically, such as restoring the Voting Rights Act, which also benefits Democrats anyway.
Trump is an anomaly. When Democrats explicitly pursue a platform of helping African Americans, they win. Truman won in 1948. Kennedy won in 1960. Johnson won in 1964. Carter was explicit in his concern for African American civil rights in 1976. Wags say that Bill Clinton was our first black president. Obama really was our first black president.
To some extent, who the candidate is matters less than the platform. Candidates are fungible. They play a role in deciding the platform, but the Party as a whole gets to decide that and the candidate has to adapt to it, for the most part. Some of the current crop of candidates will likely inspire African American voters more than others, but there is no good reason to think that they will suddenly decide that they like Trump in 2020, Trump’s own fantasy to the contrary notwithstanding. He will still be the candidate of Ben Carson and Diamond and Silk, the guy who said most Mexicans are rapists and murderers, who issued an order prohibiting the admission of aliens from predominantly Muslim countries. African Americans know better than anyone that they are next on that list.
Pursuing policies that benefit working class and poor people, and African Americans, is the right thing to do, and it is a political winner for the Democrats in 2020.