“, and subject to the jurisdiction thereof,” is clear.
The first sentence of AMENDMENT XIV was not intended to change the law regarding citizenship.
It was only to make it crystal clear that the freed Afro-Americans were citizens as they would have been if there wasn’t racism.
AMENDMENT XIV, SECTION 1 was to make it crystal clear that the freed Afro-Americans were fully citizens and to be treated as such.
The due process requirement was also clearly extended to the states in furtherance of that.
“’, and subject to the jurisdiction thereof,’ is clear”
There was a debate because the text was not clear. Senators made conflicting claims during the debate.