Next week, Americans will pause to honor the civil rights giant whose famous dream was of a society in which no one would be judged by the color of their skin. This week, however, some Americans who claim to care deeply about civil rights are judging the Democratic candidates who will debate Tuesday night by the color of their skin.

Six candidates have qualified for the Des Moines event: Joe Biden, Pete Buttigieg, Amy Klobuchar, Bernie Sanders, Tom Steyer, and Elizabeth Warren. That sextet comprises Democrats who are male and female, straight and gay, old and young, superrrich and middle class, career politicians and political newcomers, ardent East Coast socialists and pragmatic Midwest liberals.

For a bunch of Democrats, that’s pretty diverse.

Unless, that is, your idea of diversity is the kind that’s only skin-deep.

Under an ominous headline — “Only white candidates have qualified for the Democrats’ January debate” — the Washington Post reports that “the specter of an all-white debate” is prompting concern among party activists and “threatens to undercut the party’s rhetoric of inclusivity.” Indeed, the story notes, “the whiteness of the debate stage — and the top candidates — has been an issue for weeks.”

An issue for whom? For social justice warriors and the political journalists they court? Maybe. For most Democratic voters? There’s no reason to think so.

It’s true that none of the six candidates in this week’s debate are black or Asian. That isn’t because minority candidates have been excluded from the Democratic debate process. It’s because none of the candidates of color still in the race met the threshold for participating in the debate (contributions from 225,000 donors and 5 percent support in at least four polls). Neither did several white candidates.

The shrinking debate stage doesn’t reflect a failure of “inclusivity” on the part of the Democratic Party, whose voters, officeholders, and priorities make it the most racially inclusive party in American history. Reasonable minds can dispute whether the party’s criteria for joining the debates are sound, but even to hint that those criteria were adopted to keep nonwhite candidates from the spotlight is absurd. Party leaders would be thrilled if Deval Patrick, Andrew Yang, and Tulsi Gabbard had made the cutoff. (Another nonwhite candidate, New Jersey Senator Cory Booker, ended his campaign Monday.)

Unlike party leaders, however, rank-and-file Democrats haven’t shown much interest in the nonwhite candidates. Rank-and-file black Democrats haven’t shown much interest in the nonwhite candidates. It is frequently said that black voters yearn for candidates who “look like” them, but there is no evidence of it in the Democratic presidential race. Quite the opposite.

A new Washington Post-Ipsos poll of black Americans demonstrates that African-American voters yearn above all for a nominee who can defeat President Trump. A solid majority, 57 percent, say that beating Trump is their most important consideration, far above the 33 percent whose top priority is a nominee with positions close to their own. When asked which candidate they think can win, a whopping 53 percent choose Biden. Sanders runs a distant second, with 18 percent seeing him as likeliest to defeat the incumbent.

Black voters are now the backbone of the Democratic Party. They know what most sensible voters know: The “rhetoric of inclusivity” is well and good, but the point of parties is to win elections. By a robust margin, older black voters think Biden can win, while younger black voters are counting on Sanders. That’s why Biden and Sanders top the Democratic field. They are the candidates black voters support.

Obviously black voters aren’t averse to supporting a viable black candidate. Their enthusiasm for Barack Obama was off the charts. But they aren’t about to back a candidate just because his or her skin isn’t white — nor reject a candidate just because it is.

In fact, the Post-Ipsos poll found, most black Americans don’t care whether the Democratic vice presidential nominee is black.

If a white candidate wins the nomination, respondents were asked, “how important, if at all, would it be to you personally that the nominee choose a vice-presidential running mate who is black?” An overwhelming 72 percent said it was either “not so” important or “not at all” important.

Many candidates run for president. Nearly all of them fail. For black Democrats focused on November, the goal isn’t to elect a president who isn’t white, it’s to elect a president who isn’t Trump. The candidates they favor may not look like them, but they’ll be front and center in the debate.

(Jeff Jacoby is a columnist for The Boston Globe).