That’s not the only parallel with American politics less than 11 months from the election. Johnson concentrated all the Brexit votes. By contrast, the pro-Remain vote was split between Corbyn’s internally divided Labour Party, the hapless Liberal Democrats, and the Scottish National Party. For anybody contemplating the divisions of the Democratic Party as compared with the Trump movement’s fanatical singleness of purpose, now reinforced by the impeachment proceedings, this can only be worrying.

The clear rejection of Labour’s big-government socialism also looks ominous for Democrats who believe the party can lurch left and win. The British working class did not buy nationalized railways, electricity distribution and water utilities when they could stick it to some faceless bureaucrat in Brussels and — in that phrase as immortal as it is meaningless — take back their country.

It’s a whole new world. To win, liberals have to touch people’s emotions rather than give earnest lessons. They have to cease being arid. They have to refresh and connect. It’s not easy.