The story about Bernie Sanders is that he can’t win black voters. That first emerged when he lost the Democratic presidential nomination in 2016 and was reinforced by Joe Biden’s decisive sweep of Southern primaries.

This has led to reflexive assumptions about the political sympathies of African-Americans, assumptions that fail to consider the entire political context of the primaries. The massive turnout for Joe Biden by black voters certainly reflects his role as Barack Obama’s loyal vice president and the perception that, against Donald Trump, he is more “electable” than Mr. Sanders.

But consider a reason Mr. Sanders has done poorly among black voters that few are talking about: People with the most to gain by the numerous programs proposed by Mr. Sanders have also been the most disappointed by politics.

For millions, even when government “works” it is not working for them. When so many people have expressed the desire for government to do more, whether in health care, housing or debt relief, the failure of elected officials to act on any of this undermines the idea that voting is an effective way to improve lives.