Democrats who doubled down on Joe Biden after his awful TV debate are in a period of self-reflection. The rest of the party is revelling in its seemingly transformed fortunes. In the two and half weeks since Biden stood down, the US election has been turned on its head.

The Democratic party’s new nominee Kamala Harris has quickly eliminated Donald Trump’s widening lead over Biden and in some polls is ahead. These include the must-win swing states of Pennsylvania, Michigan and Wisconsin. States that were out of reach to Biden, such as Georgia, Arizona, Nevada and North Carolina, are now back in the “toss-up” category. Democratic candidates who avoided being seen with Biden when he visited their state are now queueing up to appear on the podium with Harris. If the election were held today, she would be the favourite.

Yet if America’s remarkable twists of the past few weeks tell us anything, it is that plenty more could happen in the 90 days between now and polling day. The lightning speed of Harris’s ascent should inject a note of caution. So far, however, she has played her new role with unexpected deftness.