I had to do something decidedly regrettable today: I had to relegate my high-school mentor, a man who used to be one of my most beloved teachers, to the “Junk/Ignore” filter on my e-mail account.

The man I knew in my youth had always seemed to be a compassionate, tolerant man. He encouraged his students to see others’ points of view and to be open to new ideas. Literary experimentation was a hallmark of his creative writing class.

In the decades since I finished high school and he retired, I stayed in contact with him and, on occasion, visited him during my rare returns to the old hometown. It had always seemed nice to catch up with him.

In recent years, however, he has become increasingly reactionary, right-wing, and intolerant. It started during the Bush years, if I recall correctly. He began forwarding ugly, racist e-mails, messages full of jingoistic anger, homophobic lies, and vehement anti-Liberal, anti-Democratic vitriol.

At first, I tried arguing with him. I attempted to refute his mass-forwarded lies. It was a waste of my time. I soon saw that he was beyond reason. He had drunk the Karl Rove Kool-Aid and gone back for refills.

In the interest of peace, I asked him — and, eventually, I implored him — to exclude me from his torrents of hate and bigotry. But the avalanche of stupidity continued unabated and gained momentum after the election of Barack Obama.

Then, for a brief while, his messages tapered off in frequency. Over the past few days, however, it has begun anew. I see no point to arguing with him, or even to asking him to stop. I have simply chosen to add his e-mail to my spam/junk filter.

It saddens me greatly to have been pushed to this point, but when someone cannot respect a polite difference of opinion, and chooses to bombard me with hate-filled propaganda despite my entreaties for peace … that’s the end of the line.