US President Joe Biden’s decision to withdraw from the presidential race was the correct thing to do. After a poor debate performance against Republican candidate Donald Trump and low opinion poll ratings mainly linked to public concern about his age, Biden did what was right for his country.

There is a great deal at stake in November’s US election, and a victory for Trump would severely dent America’s credibility and make the world a much more volatile place.

Biden’s replacement as the Democratic Party nominee, Kamala Harris, has now made the prospect of a defeat for Trump much more possible.

Despite voters’ lack of enthusiasm for Biden, the US president will leave office next year with a record he can be proud of: a strong transatlantic alliance, a US-led global coalition to support Ukraine after the Russian invasion, a robust economy, record job creation, historic investment in the infrastructure, lower prescription drug costs, record health insurance coverage, cancellation of student debt, the most significant climate law ever, and a successful handling of the COVID pandemic.

Harris, who has been endorsed by the entire Democratic Party leadership, numerous Democratic members of Congress, governors, as well as Barack and Michelle Obama, and Bill and Hillary Clinton, has a few weeks to convince voters that she is a far better alternative to Trump and that the Republican candidate is a threat to the rule of law and American values.

The first signs are already encouraging: opinion polls show the gap between the two presidential candidates has narrowed considerably, with Harris leading in some.

However, winning the popular vote is not enough, and Harris will have to campaign hard in crucial swing states such as Pennsylvania, Wisconsin, and Michigan – and appeal to working class and rural voters, some of whom have been leaning towards Trump – to win the Electoral College vote and secure the presidency.

Harris now has the advantage of being the younger candidate in this race – she is 59 while Trump is 78, but she remains relatively unknown to many Americans.

While she will rightly stress the achievements of the Biden administration – which she forms part of – she will also need to explain what she will do differently to Biden – such as how she will tackle the country’s border problem, how she plans to address people’s economic concerns on a micro level, and how far she is willing to go to exert pressure on Israel to stop its horrendous war in Gaza.

There is absolutely no doubt that Trump is not suited to be the next American president. He is a convicted felon, a pathological liar and has expressed admiration for Vladimir Putin. He still refuses to accept that Joe Biden won the 2020 election, he has said he wants to be a dictator “for one day”, and urged people at a rally recently to vote “just this time” as they “won’t have to do it anymore”.

Apart from brandishing the press as “enemies of the people”, Trump’s foreign, social, and economic policies are dangerous, divisive and confused. Significantly, not one of Trump’s cabinet members from his previous presidency – as well as his own vice president, Mike Pence – have endorsed him. And the former president now surrounds himself with ‘yes men’ who share his populist far-right agenda – which gives us a good idea of what type of people he will appoint to his administration if elected.

In a volatile world, the last thing we need is a US president who refuses to moderate his rhetoric or behaviour. He must be defeated in November.