So we're clear, Taney was referring to Africans who were slaves at the time, who were slaves then were freed, or who were descendants of slaves.
In response to your statement, I'm sure there were some free blacks who were citizens of their state complete with voting rights. But they were not citizens of the United States (according to Taney).
At the time of the Constitutional Convention, the phrase "the people" had a specific meaning. It did not mean all persons or even all citizens. It referred to those who were full citizens -- those who could vote, run for any office, and who owned land (rich, white, adult male citizens). This excluded women, children, slaves, foreigners, and visitors.
"The people" were in charge and they had the most to lose. The U.S. Constitution was written for them (unless specified otherwise).
Oh, I agree with that. I just believe Taney was wrong in this belief.
It referred to those who were full citizens -- those who could vote, run for any office, and who owned land (rich, white, adult male citizens). This excluded women, children, slaves, foreigners, and visitors.
One of the numerous problems with Taney's theory is that "the people" changed quite significantly between the 1780s and the 1850s, as the states expanded the franchise to include all white males. This was apparently just dandy with him.
So, states can legitimately, accordingly to Taney, change the definition of a "full citizen of the United States" in some ways but not in other ways. There is absolutely no justification for this distinction in the Constitution or in statute or common law. But Taney finds one, apparently because he is offended by the prospect of Africans as citizens and equals.
A much greater mind than mine has addressed the issue is considerable detail. Let me refer you to the man who led the successful fight against this iniquitous decision.
http://teachingamericanhistory.org/library/index.asp?documentprint=52