You asked for another scholar who extends Smith's point

Yes—and this is actually a better way to construct the paragraph.

You can use Smith for the conceptual distinction, then use another scholar for the historical proposition you want to establish.

For example:

Rogers M. Smith (2022) distinguishes legal citizenship from lived citizenship, drawing attention to the difference between formal legal rights and the social, political, and economic standing necessary for civic equality. [Smith citation]

Then:

Another historian's evidence can establish how that distinction operated in the post-emancipation United States.

That prevents Smith from having to prove your entire historical argument.