Nonetheless, Shropshire cautioned,

eight months of continuous advertising, coupled with the opening of field offices in black communities, could have the intended effect of peeling off enough voters to improve his standing by a couple of points, while raising enough doubt about the Democratic nominee that other voters simply stay home, à la 2016.

The prospect of such a setback, Shropshire noted, shifts the burden back onto Democratic donors and allied organizations to mount a full-court press on those “who voted 3rd party or did not vote in 2016,” in order to avoid a repeat of the election results that year.

Ismail K. White and Chryl N. Laird, political scientists at Duke and Bowdoin and the authors of a new book “Steadfast Democrats: How Social Forces Shape Black Political Behavior,” argue that Trump’s efforts to win black support will be futile. In a February Atlantic essay, they write:

Political solidarity has been a crucial political asset of black Americans during a long struggle against racial injustice, and a few symbolic gestures or policy initiatives won’t win significant black support for Republicans.

They make an intriguing — and eminently reasonable — case for the strategy Republicans should adopt if they are in fact serious about winning over African-American voters:

If Republicans want black votes, their strategy should be simple: End racial segregation — which not only leads to societal inequities that most African Americans strongly deplore, but also reinforces the social structures and conventions by which black adults encourage one another to vote Democratic.

Continued segregation, they write, plays a crucial role in maintaining black loyalty to the Democratic Party:

Racial segregation — the very phenomenon that created a need for African-American political unity — also allows the group to censure defectors. Because of spatial segregation, many African Americans have social relationships almost exclusively with other black people. As a result, these black individuals then find themselves compelled to either accept the dominant political beliefs of the racial group or risk loss of status within these largely black social networks.

Vincent L. Hutchings, a political scientist at the University of Michigan, noted that the Trump campaign “recognizes that no Democratic presidential candidate can win the White House without near unanimous support from blacks, coupled with relatively high turnout.” As a result, “the real issue is whether he can peel off enough to make a difference, or if he can diminish support for the Democratic nominee.”

While there are “some things that the Trump administration can tout to potentially appeal to a critical slice of black voters, e.g., criminal justice reforms, low unemployment, etc.,” Hutchings argued these issues will not “make much of a dent.” Group loyalties, both partisan and racial, “are far more important. And, these group loyalties — particularly in a general election campaign — are likely to encourage considerable, and enthusiastic, opposition to the Trump campaign.”

Pearl K. Dowe, professor of political science and African-American studies at Emory University, shares Hutchings’s doubts.

“Trump’s outreach is not about picking up a significant number of African-American voters but to message to black voters that Trump may not be as bad as they believe,” Dowe wrote by email.

The Trump campaign could succeed in influencing “a few black voters who might decide to stay home if they feel there isn’t a real option that could positively impact their lives.” But, Dowe argued, “the strong disdain black voters have for Trump” will produce a “higher turnout rate for African-American voters and an overwhelming support for the Democratic candidate regardless of who it is.”

Sekou Franklin, a political scientist at Middle Tennessee State University, is optimistic about Democratic prospects with black voters, but he added some significant caveats in his email:

Blacks believe that this is a do or die election with high stakes, and many see Trump as threat to their long-term livelihood. This message will be reinforced by black leaders, civil rights groups, and opinion makers — and these social pressures matter in terms of consolidating the black vote.

However, Franklin noted, if

Trump were to make inroads among black voters — and this is a big IF — it will be among black men versus black women. Black men voted for Trump at a higher rate than black women in 2016, and black women are the most committed Democratic Party voters.

In addition, Franklin cautioned,

If a civil war breaks out inside the Democratic Party between Bernie Sanders’s supporters and another candidate” the conflict “could cause chaos such that young blacks could choose to stay home and not vote on Election Day, which would give Trump an advantage.

Franklin predicted a replay of 2016 in the event that Joe Biden is the Democratic nominee, with the Trump campaign stressing Biden’s vote for the 1994 crime bill. Both Franklin and Dowe agreed this line of attack was effective against Clinton in 2016, and both argued that it received strong reinforcement via Russian interference:

In 2016, “Trump’s ads and Facebook posts were effective, but they were augmented by an even more effective foreign intervention according to the U.S. Senate Intelligence Committee report,” Franklin wrote. The Senate Intelligence Committee found that Russia engaged in a massive disinformation campaign, Franklin noted, and “it was extraordinarily important in misleading blacks in order to convince them that there was no difference between Clinton and Trump.”