To clarify, I’m talking about writing a candidate in during the general election, not voting or caucusing for a candidate who’s on the ballot during the primaries.
Wikipedia defines a protest vote as: “A protest vote (also known as a blank vote or white vote) is a vote cast in an election to demonstrate the caster’s dissatisfaction with the choice of candidates or refusal of the current political system.”
And Dictionary.com defines it as: “a ballot cast for a candidate with a minimal chance of winning, to register dislike for the other candidates.”
I think my use of the phrase is consistent with those definitions.