Verbal abuse sometimes has a way of stiffening the spine. That seems to be the case for Senator Susan Collins, the moderate Republican from Maine. With the debate on impeachment getting white hot, Ms. Collins’s office has released a sample of the appalling voice mails being left for her. Roughly one out of every 25 callers sounds like this:

Male voice: “Wow, what a vile piece of garbage you are, Susan Collins. Sorry. But those of us with a brain in the United States, which is about more than half the country, see exactly what...