What race issues was senator johnson likely referring to in california and in the south? given who
supported the treaty (see doc c), why might he have made this argument?

what are the options so i can answer it

sedition laws violated the first amendment to the u.s. constitution, which protects freedom of speech and the press.

it would mean for other coutnries that the speak of them may cause a war or a person from another country talking about it could get arrested and the countiry and other contries could count that as rasisim and start a race war.