Less than 24 hours after Joe Biden announced he was abandoning his re-election bid, the path for Vice-President Kamala Harris to secure the Democratic presidential nomination is clearing. That may end up being the easy part. The most formidable challenge – defeating Republican nominee Donald Trump in November – is still to come.

Her elevation to the top of ticket would bring new strengths for the Democrats, but it also exposes weaknesses that were less of a concern with Mr Biden. According to recent polls, Ms Harris trails the former president slightly – a roughly similar position to the one Mr Biden found himself in before his historic announcement. But there may be more room for those numbers to shift as we move from a hypothetical matchup to a very real one.

For at least a moment, Democrats have a jolt of energy after more than three weeks of intense hand-wringing over the president’s fitness and ability to sustain his campaign. All of Ms Harris’s leading potential rivals for the nomination have endorsed her, as has former Speaker of the House Nancy Pelosi – who remains one of the most influential players in Democratic politics. This is, still, shaping up to be a tight race in November - a condition that reflects deep partisan trenches in American politics and the distaste many voters have for Trump as a candidate.

The vice-president’s primary challenge – and opportunity - will be to capitalise on this Trump aversion, attract centrist voters in key swing st.