Please just let me get this off my chest. Yesterday, I heard a politician claim that “the threat of terrorism cannot be underestimated.”
Now, this isn’t the first time I’ve heard this, or similar statements. My brain signalled that the sentence contained something that made no sense and then just had to work out what it was.
“cannot be underestimated” means that, however hard we try, however much we underestimate the threat, we will never succeed in minimising it enough for our estimate of the threat to be as low as the actual threat. This is pretty much the opposite of what the speaker intended.
What the speaker actually means is either “the threat of terrorism cannot be overestimated” – in other words, the threat is too huge to estimate or, more likely, “the threat of terrorism shouldn’t be underestimated” – in other words, we shouldn’t get complacent.
Oddly enough, I tend to hear this most often in relation to sport or politics but then, perhaps I shouldn’t underestimate the amount of football I listen to.
Call me a pedant, if you like, but “cannot be underestimated” is lazy bollocks. Almost on a par with the American “I could care less” which has somehow morphed from the correct, British, “I couldn’t care less.” Double negatives, they’re so complicated.