1595, from L.L.
nullificare "to esteem lightly, despise, to make nothing," from L.
nullus "not any" (see
null) + root of
facere "to make" (see
factitious).
Nullification in U.S. political sense of "a state's refusing to allow a federal law to be enforced" is first attested 1798, in Thomas Jefferson, from L.L.
nullificationem (nom.
nullificatio) "a making as nothing."