Until the day she died, Barbara Bush kept a clock next to her bed that counted the days until Donald Trump was gone. The former first lady’s timekeeping was upbeat: she assumed a one-term presidency. Most of the world is in the late Mrs Bush’s camp. To judge by the absence of diplomatic initiatives, the west is also marking the calendar until Mr Trump leaves office. The same goes for non-Trumpian America. As Joe Biden, the Democratic frontrunner, keeps saying, Mr Trump is an “aberration” — as though time has briefly gone astray. All we need is to wait out the clock then reset it.

There are two problems with this view. The first is that you cannot recapture lost time. The world will not reboot to where it was before Mr Trump took office. A defeat for Mr Trump would be bad news for Saudi Arabia, Russia and North Korea. Mr Trump has licensed Saudi adventurism, validated Vladimir Putin’s world view, and given Kim Jong Un a coming-out party to remember. But it is unclear Mr Trump’s exit would make much difference to China. The most striking change to have happened since he took office is the speed with which Washington has embraced the so-called new cold war. Mr Trump’s successor would be as likely as he to see China as America’s main rival.

Europe, Japan, Canada and Australia should also be wary. Although Mr Trump’s departure would herald a big change in tone, there would be continuities on substance. Mr Trump’s Democratic successor would be just as impatient with Europe’s low defence budgets. Polls that show most Americans in favour of free trade are misleading because they miss the intensity of opposition. Decisive factions on both ends of the spectrum are strongly opposed to new deals — with allies or others. In the past, Democratic presidents could rely on Republican lawmakers to pass their trade deals. Those days are probably over. The logical step for any US president to contain China would be to rejoin Barack Obama’s Trans-Pacific Partnership. Yet even Mr Obama could not persuade Democrats to vote for the TPP. It is doubtful a President Elizabeth Warren or a President Kamala Harris would even try. Ms Warren’s foreign policy has been called “Trumpism with a human face”.