call them and tell them they were wrong/right in their vote, and that you do/don't support their decision. "your vote on X has seriously caused me to reconside

call them and tell them they were wrong/right in their vote, and that you do/don't support their decision. "your vote on X has seriously caused me to reconsider my support of the NDP and you as a candidate. this is a heavyhanded measure that bla bla bla bla..." or similar such statement.