nullifier

nouns

an advocate of nullification; someone who believes that a state can resist federal laws
nullifier
is derived from
nullify
is a type of (narrower)
a person who pleads for a cause or propounds an idea
advocate, advocator, exponent, proponent
an official who can invalidate or nullify
"my bank check was voided and I wanted to know who the invalidator was"
invalidator, nullifier, voider
is derived from
nullify