(EDIT: This question has now been reopened. Thank you all for your help.)
This question asked about the following passage from a news report:
Pentagon experts on Friday said it was impossible to imagine that the missile could not have been fired without Russian help.
The questioner was puzzled by the presence of the word not, and wondered if it was a mistake, or if the wording was simply idiomatic. The question currently has a score of -4, and has been closed for being "off-topic," because shame on the asker for not consulting "commonly available references."
Here's the thing, though: The sentence is wrong, and the questioner is absolutely right. As written, the sentence states that the missile could have been fired without Russian help, and that to think otherwise is impossible. In context, that is clearly the opposite of what the article intended to say. This is an example of the class of errors that is sometimes called misnegation, most likely caused by the reporter or editor becoming momentarily lost within the difficult triple negative combo of impossible, not, and without. Misnegation is an interesting phenomenon, and there's nothing basic about it; indeed, it's clear from the reaction to the question that some people here were tripped up by it just as the original reporter and/or editor were. It's difficult to see why a topic that's provided grist for more than a dozen Language Log posts should be considered "off-topic" here.
So why, then, should this be considered GR? Please help me understand which commonly available reference or references could be used to answer this question. (Bear in mind that the questioner did in fact show all signs of knowing what "not" means; the question is whether "not" in this context is idiomatic, not whether it's wrong as strictly parsed.)
In fairness, it should be noted that the question as originally asked was fairly spartan and low-quality, which I assume explains most of the otherwise mystifying downvotes—and kudos to KitFox for whipping the question into shape with a very good edit. Still, it should be noted that at least three of the close votes on this question came after KitFox edited the question. This seems completely indefensible to me, and the only explanation I can think of is that the close voters did not pay enough attention to the question they were voting to close. That's not how it's supposed to work. If we're going to close questions because the askers didn't do enough research, we owe it to the askers to at least make a token effort not to commit the same sin we accuse them of committing.
Please help me reopen this question.