Nullifier and Proponent

Nullifier noun - An advocate of nullification; someone who believes that a state can resist federal laws.

Proponent and nullifier are semantically related. In some cases you can use "Proponent" instead a noun "Nullifier".

Proponent noun - A person who actively supports or favors a cause.

Nullifier and proponent are semantically related. Sometimes you can replace term "Nullifier" with "Proponent", this nouns are similar.