Some of the best ideas on just about any topic have come through our letters to the editor section. Also some of the most pointed, in which a writer neatly punctures in just a couple of sentences an extravagantly wrong editorial concocted here or a commentary on the op-ed page. These are most welcome even when they do show how badly our reach has exceeded our grasp.

The absolute worst response, also pointed, has been received by a couple of letter writers in recent months. At least two writers whose critical letters about President Bush were published have subsequently received threatening, anonymous replies accompanied by box cutters. The threats have said something like, “Remember what this is used for before you write again.”

We hesitate to write about this for fear that it might achieve what the anonymous person wants – silenced critics, attention – or might inspire copycats. We certainly do not want to discourage readers from expressing themselves on our pages. But we cannot ignore this threat and believe it would be unfair to readers to not inform them.

According to Bangor Police Chief Don Winslow, “99.9 percent of these are idle threats, but you never know when you will get someone who is unstable and will carry through with it.” Chief Winslow adds that others who have been similarly threatened should contact their local law-enforcement agency.

Another worthy suggestion comes from Clark Hughes, the editorial page editor at The Bay City (Mich.) Times, which has militant groups, and subsequently some strong opinions, in its area. His practice has been to let those threatened have a sentence in their next letter to denounce the behavior.

“One guy even called on the sneak to stand up on his hind legs and debate his views in the open,” he said. That sounds like the best response – a demand for more civil speech and a strong suggestion that the threatener stop hiding behind the blade of a knife.