The stage for the Democratic presidential debate in Detroit on July 30. (Anthony Lanzilote/Bloomberg)
Opinion writer

The 10 Democratic presidential candidates left on the September debate stage (more may come back in October) include three female senators, one gay mayor, a Taiwanese American business leader, a Latino former Cabinet secretary and mayor, two African Americans (one of whom is a woman) and three straight white men. Democrats can rightly claim that their party’s politicians look more like America than ever before. Certainly nonwhite voters remain a mainstay of the Democratic Party. Yet support from these voters is limited to a very few candidates.

There has been a lot of coverage about South Bend, Ind., Mayor Pete Buttigieg’s struggles with African American voters. However, plenty of other candidates on that stage will have little or no African American support. Amy Walter of the Cook Political Report notes that 24 percent of the 2016 Democratic electorate was African American. In four of six recent polls that broke out African American voters, she found that former vice president Joe Biden leads among African American voters by 19 to 36 points.

In the Quinnipiac poll, only four candidates — Biden and Sens. Kamala D. Harris (Calif.), Bernie Sanders (Vt.) and Elizabeth Warren (Mass.) have at least 7 percent support among black voters. Sen. Cory Booker (N.J.) has 3 percent, and none of the others in the next debate has even 1 percent support among black voters.

In the Fox poll, Biden has more than twice the support among black voters as does, the second-place candidate (Sanders), and only four candidates have 8 percent or more, with Booker and Beto O’Rourke at 6 percent. Among all nonwhite voters, only four contenders get 7 percent or more.

Biden so dominates among African Americans that there is not a plethora of non-Biden black voters. With two very white states, Iowa and New Hampshire, kicking off the primary process, those with little or no African American support pay little penalty in the early goings. But it’s hard to imagine that if Biden keeps his support among African American voters (not to mention older voters, who overwhelmingly favor him) that someone else can piece together enough votes for the nomination. The media have tended to focus on what happens to the moderate voters if Biden fails, but the more important question is whether any other candidate can dominate among African Americans to the extent Biden has.

This remains a nagging concern for Warren, who generally draws in the high single digits among African Americans. It also explains why Harris has made a huge push in South Carolina, doing multiple events last weekend. She may stand to gain the most from African American voters as well as voters who aren’t “very liberal” (Sanders’s and Warren’s strong base) should Biden falter.

In all the talk of electability, the media continue to posit that the “safest” candidate is a white man with appeal in the Upper Midwest. That assumption, I’ve suggested, is misguided, considering the importance of the votes of African Americans and women in the suburbs. Candidates who seem to leave those voters cold don’t seem all that electable.