American politics has taken a dangerous turn

But this time really could be different for Republicans. Goldwater’s surge came late; Mr Trump has mesmerised crowds, and been rewarded in the polls since July. Some Republican grandees who detest Mr Cruz even more than they despise Mr Trump have fallen in behind the billionaire. Perhaps on the day people won’t turn up for either man; perhaps the two of them will throw enough vitriol to destroy each other; perhaps what is left of Mr Bush’s $100m war chest will leave the elite time to mount a counter-attack. As of now, both populists have a chance of taking the fight to the convention and even, barring a backroom establishment deal, of winning the nomination.

That prospect worries this newspaper. Neither Mr Trump nor Mr Cruz offers coherent economics or wise policy. Neither passes the test of character. Yet, merely by being on the ballot in November either would come close to the presidency.

General elections have become 50:50 affairs, determined by a few votes in a handful of states. Mrs Clinton is not a good campaigner; Mr Trump and Mr Cruz are. In so far as he has policies, Mr Trump borrows freely from right and left. He could win votes by tacking brazenly to the centre. In a close race, a terrorist attack or a scandal near polling day could be decisive.

Pessimism about America is misplaced. The economy is in better shape than that of any other big, rich country; unemployment is low; so is violent crime. But mainstream Republicans have pilloried Barack Obama with such abandon that they are struggling to answer Mr Trump and Mr Cruz. If anyone should regret the spectacle about to unfold, it is they.