"I’ve been using 'Black' and 'African-American' somewhat interchangeably here. But there’s a good case to be made that this is a mistake..."

"... that 'Black' denotes a racial category and is inclusive of Americans throughout the African diaspora, while 'African-American' refers to national origins, specifically descendants of American slaves. But some Black Americans who are not descendants of slaves claim the term 'African-American,' and some who are descendants do not. And 'Black' also tends to be used in reference to the cultural heritage of Americans of African descent. This column is about 'blackness' as a category and a culture, so I will stick with 'Black' as my preferred terminology. My main point is this: Black American identity within the United States emerges from the interaction between structures of oppression — slavery, the slave trade and race hierarchy — and the needs and goals of those enmeshed within them.... Because of heritage, upbringing and the realities of American racism, [Kamala] Harris calls herself Black and is also understood as Black by people within and outside the Black community.... There has never been some essential element to blackness, no singular quality or attribute that makes someone a Black American.... [I]t might be better to ask 'Why do so many Americans of African descent claim blackness?'"

From "Black Like Kamala/Republican efforts to deny Senator Harris’s identity as an African-American and turn her into a noncitizen are destined to fail" by Jamelle Bouie in the NYT, reacting to Mark Levin's statement "Kamala Harris is not an African-American, she is Indian and Jamaican. Her ancestry does not go back to American slavery, to the best of my knowledge her ancestry does not go back to slavery at all."

Notice that Bouie speaks of "claiming" blackness, and Levin stresses outwardly checkable facts. It's a bit like the way people of the left and the right speak about gender.

By the way, why would you capitalize "Black" but not "blackness"?