Whenever she considers voting in an election to select one candidate for a position and there is at least one issue important to her, Kay uses the following principle in choosing which course of action to take: it is acceptable for me to vote for a candidate whose opinions differ from mine on at least one issue important to me whenever I disagree with each of the other candidates on even more such issues; it is otherwise unacceptable to vote for that candidate.
Statements
conditional (whenever - Left side, sufficient)
Disagree w/ other acceptable to vote for candidates on greater → candidate X, even if # of important issues disagree w/ X on one or more important issues
conditional (otherwise - negate previous trigger)
don't disagree w/ other unacceptable to vote candidates on greater → for candidate X, if # of important issues disagree w/ X on one or more important issues
In upcoming election, there is only one important issue to Kay, and only Medina (of the three candidates) shares her opinion.
Evaluate
It looks like in this election, the only acceptable person Kay can vote for is Medina. Kay could otherwise not vote, but were she to vote for Legrand or Norton she'd be breaking her rule.
She's not allowed to vote for people who don't share her view on an important issue, unless the other candidates mismatch with her view on a greater number of important issues.