The idea of a dogwhistle is that it is so high pitched that only a dog can hear it. When applied to politics, it generally refers to a message tailored to a narrow constituency that most people outside that constituency might not notice.
But sometimes a dogwhistle is pitched so low that everyone can hear it. Then that happens, things get decidedly weird.
Last night, at the presidential debate, our president pitched a dogwhistle so low it was essentially in the basement. He suggested to far right white-supremacists, in a very obvious way, that they should be ready to disrupt the election process by means of physical violence.
Never thought I would see something like that my lifetime.