I t is a long time since Twitter was anything like birdsong, but that’s the way of everything. An idealistic media designed to give voice to the silent falls to the grifters: Donald Trump, a man who tried to overthrow the republic, was readmitted at the weekend to wreak havoc again. No new form of communication changes you. It merely magnifies what you are, and Twitter functions above all as a mirror in which the angry, the despairing and the numb are yet more so. It is congenitally unseemly: politicians announce policy that should be announced elsewhere, where it matters;...