The legal right to expatriation means that you have the right to
a. renounce your citizenship.
b. retain your citizenship when living abroad.
c. be given safe haven by american embassies abroad.
d. have an expert witness testify at a trial brought against you.

i'd assume india mainly because of how isolated japan was.   plus it is a whole china away.

regarding the law, the 15th amendment was specifically designed thinking in the rights of black free men.

even though ratified on february 3, 1870, the promise of the 15th amendment would not be fully applied for a long time.poll taxes and literacy tests would allow southern states disenfranchise african americans. only in 1965 the voting rights for african americans would be actually able to vote in the south.

in 1965, president johnson signed the voting rights act, which aimed to overcome legal barriers that prevented african americans from voting as it was guaranteed by the 15th amendment to the u.s. constitution.