If we go down this road all I have to do to win against my competitors is to get someone to start accusing them of anti-Semitism (works well if they've ever criticised Israel), sexism (helps if there are a majority of men on the board) etc. etc.
Generally referred to as a smear campaign (but not to be confused with 'test', although recent concern over numbers taking up the latter might suggest some actual confusion over the two)