I read a book about the US Secret Service a couple of years ago. They investigate all threats against the US president. Many of them come from people who forgot to take their medication.  Usually, it takes a visit from the local constabulary to set things straight. Amazingly, all lot of hate messages against the US president comes from federal prisons.

Marc Lalonde was a federal cabinet member in the Trudeau senior years. He received many threats, He said he wasn't worried about the open hate in letters or telephone calls. He was more worried about the cranks that didn't send in letters or telephone calls.