Will Donald Trump turn out to be a good President? Of all the uncertainties facing the world this year, that is the big one. Nothing matters more.

It is a measure of the greatness of the United States that this should be so. It is why much of the American establishment is so cautious, and why European leaders are so concerned. If the EU were to collapse this year – unlikely, but not unthinkable – that would upset a lot of people in Europe, but it not be a disaster for the world as a whole. If, however, the US were to make a really big policy error, then 2017 would become a catastrophe.

Looking back, the US has had its fair share of bad presidents. In the past century Richard Nixon is among the most reviled, though his big call – that the US needed a rapprochement with China – now looks remarkably prescient.

Some are simply unlucky. Herbert Hoover’s name lives on in one of America’s great public works projects, the Hoover Dam. That was surely the right response to the Great Depression, but Hoover, who took office eight months before the Wall Street crash of 1929, was overwhelmed by scale of the economic collapse and lost to Franklin D Roosevelt in 1932.

Nor is the judgement of the electorate at the time of office much guide to the judgement of history. Warren Harding, President from 1921 to 1923, is now ranked as one of the worst-ever US presidents, remembered now for a series of scandals involving not just himself but members of his cabinet. These emerged after his sudden death. Yet he has been elected by a landslide and in office was one of the most popular presidents.

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And the famous checks and balances that are supposed to limit the power of the President? Well, they have not always worked in favour of wise policies. Congress has not always got things right.

Hoover signed the Smoot-Hawley Tariff, which led to a collapse in world trade and prolonged the depression, but he did so only reluctantly. And the isolationist lobby in Congress inhibited FDR’s efforts to give more support to Britain in the Second World War, until the Japanese attack on Pearl Harbour forced the issue. Even then, the US hesitated in declaring war on Germany. Fortunately, four days after the attack, Hitler declared war on the US and that settled the matter.

And President Trump? It is sometimes difficult for a Briton (albeit one with family in the US and a lifelong affection for the country) to write credibly about US politics, but here are three thoughts about things to look for in the months ahead as Trump takes office.

The first is that the US has a very resilient political system. We may start to see evidence of that resilience quite soon. It could come in the confirmation process for cabinet appointments, where hopefully Congress will behave in less partisan manner than it did over the Obama nominations. It will come in the decisions of the Federal Reserve, as the US returns to more normal monetary policy. The Fed is independent, but needs to have that independence protected. And it will come in the courts, not so much in the appointments to the Supreme Court, though that is a huge issue, but rather in the way lower courts deal with practical issues.

I suppose the key question here is whether this Congress wants to be remembered as a successful one, which requires a greater degree of harmony than in the past eight years. Politics should never be a game of “winner take all”, and over the years American politics have respected the losing side.

The second thought is that presidents are remembered for getting a few, perhaps just one, really big decisions right. We remember John F Kennedy for his masterly handling of the Cuba crisis, the closest the world came to nuclear war since 1945. That on the face of it is greatest concern about Donald Trump. Most people have some kind of filter between what goes on in their brain and what comes out of their mouth – or their Twitter account. The Donald, we know, does not. That reflects the transformation of communications more generally, where what was bar-room banter has been transformed into messages read by millions.

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But words do matter. The danger is partly that abuse of language, or indeed abusive language, will nudge the world towards some crisis that requires the US President to get the big decision right. It is also that the language will make it harder for him to do so. Language is freedom; but if abused it can box you into a corner.

The third thought is that, on a long view, this not a particularly dangerous moment for the world. The US has to manage its relations with two great powers: Russia and China. It has to fit in with the global movement towards more responsible treatment of the environment. And it has to find ways of sharing the wealth its great economy generates more fairly among its people.