“Here is a good rule of thumb for dealing with Donald Trump,” said Ross Douthat in The New York Times: “everyone who gives him the benefit of the doubt eventually regrets it.” This was true of contractors and creditors throughout his business career. It has been true of his colleagues and spokesmen since he entered the White House. And it’s now true of all those journalists, like me, who were inclined to dismiss claims that Trump’s inner circle had directly colluded with Russian officials during the 2016 presidential campaign. I thought it was pretty unlikely to have happened, and that even if it had, the odds of ever finding proof of it were “vanishingly low”. Now, thanks to the release last week of some emails to and from Trump’s 39-year-old son, Donald Jr – the “Fredo Corleone of a family conspicuously short of Michaels” – we have that proof.

The emails “could hardly be more incriminating”, said Ruth Marcus in