Everyone is suddenly talking about the Deep State – the configuration of spy agencies, career bureaucrats, and overseas spooks whose murky omnipresence has been brought to light by President Trump's contention that he was "wiretapped" by his predecessor.

With his usual imprecision, Trump managed to confuse the issue by ascribing the surveillance to Barack Obama, and so naturally spokesmen for the former President had no trouble batting this charge away. But as a former Obama speechwriter put it:  "I'd be careful about reporting that Obama said there was no wiretapping. Statement just said that neither he nor the [White House] ordered it."

And then there's the word "wiretapping": this brings to mind the old-fashioned physical "bug" that our spooks used to plant on their target's phone lines, installed in the dead of night. But that isn't how it's done anymore.