The contrast could hardly be starker. On 20 January, the first black president of the United States left the White House with his family for the last time – his departure as symbolic as his arrival had been eight years before. By mid-August of the same year, his successor, Donald Trump, is caught between what is required of the leader of a civilised country in the 21st century – let alone a country that has cast itself as the leader of the free world – and his combative instincts as an American of a certain tradition to say things as he sees them. If anyone needed proof that the race issue in the United States remains raw and divisive, here it was.

Confronted with clashes in an American college town between protesters brandishing Confederate flags, Ku Klux Klan insignia and even swastikas and their anti-racist opponents, clashes in which a car was used as a weapon and a civil rights activist was killed, clashes moreover that the forces of law and order were insufficient, or unwilling, to halt, the president offered a response that fell short by so much as to unleash critics of his fitness for office all over again.

It was not hard to figure out what he needed to say, at least as an initial response. Yet his first response was to say nothing. His second was to declare both sides equally to blame. His third response – heavily scripted – was to condemn racists, white supremacists and the Ku Klux Klan (was that so hard?), before returning 24 hours later to the “both sides behaved badly” theme. In the end, the US was presenting a face to the world that exemplified the sort of moral equivalence and ambiguity that it has traditionally deplored in others.

Suffice it to say that it is not how many, probably most, in his own country, or even his own Republican party saw what happened. The likes of John McCain – yes, that awkward, principled senator again – were quite clear in their condemnation. American second world war veterans spoke of their part in the fight against nazism. The Trump Tower press conference showed the president duelling – no less – with mainstream journalists, who challenged his every word live on television.

Even the relatively new secretary general of the United Nations, António Guterres, weighed in with a statement that did what any post-civil rights era president of the US should have known how to do: condemn any manifestation of racism, immediately and unambiguously, out of hand. “Racism, xenophobia, antisemitism, Islamophobia are poisoning our societies,” he said on Twitter. “We must stand up against them. Every time. Everywhere.” What, you have to ask, is so hard about saying (and believing) that?

The swastikas being paraded at Charlottesville had immediate resonance in Europe

At which point is it worth asking what has driven Trump’s equivocation on Charlottesville and how can, or should, US allies respond? Already there are those arguing that this will prove a turning point at which the US president showed his true colours and lost all claim to moral authority, at home and abroad. I doubt this – for two reasons.

Abroad, it must be questionable how much moral authority, if any, Trump wields at all. You can contest the longstanding US boast that it stands up for universal values, a boast that lays it open to accusations of double standards – but Trump has never actually boasted that. Indeed, he has expressly dissociated himself from the idea that the US would tell other countries how to organise themselves. It may be we Europeans who are finding it hard to adjust to a US leader who does not see himself, or perhaps even his country, as a beacon for the free world.

The swastikas being paraded in Charlottesville had immediate resonance in Europe, where the German chancellor, Angela Merkel, was first to condemn what happened, swiftly followed by Theresa May. But both stopped short of condemning Trump other than by implication, May’s spokesman saying that his words were “a matter for him”. The scenes beamed around the world from Charlottesville and Trump’s reaction, however, will make it even harder than it already was for European countries to host the US president in future. That promised UK state visit looks an even more distant prospect.

But there is another aspect of this episode that should not be neglected. The progress of civil rights and the election of Barack Obama have perhaps obscured the extent to which race remains a running sore in the US and how far the civil war remains unresolved in parts of the south. What precipitated the clashes at Charlottesville was the proposed removal of a statue of a Confederate hero, Robert E Lee. Monuments, like flags, can be incendiary – as they are in Northern Ireland and elsewhere where history is contested. It would be far too generous to Trump to suggest that this awareness dictated his equivocal reaction. But these events should invite all those who believe that the US has largely overcome its racial divisions to take another look.

• Mary Dejevsky is a writer and broadcaster