It is in our interest for any American presidency to be successful, but we have a particular reason for wishing Donald Trump’s to be.  He is sympathetic to Brexit, because he sees parallels between the EU referendum result and his own electoral victory, and favours a trade deal with Britain.  Boris Johnson did not quite say that we will be “in the front of the queue” on his return from Washington this week, but he came as close to doing so as he judged to be prudent.  We need Trump to be a force for a good Brexit deal, working against those who want a punitive one.

His presidency may indeed work out well, but the President-elect faces unique problems.  These are not so much with America’s security and intelligence services – there is a long history of former American presidents falling out with them, though none had the opportunity to do so Trump-style on social media – as with his own party, which dominates Congress.  On paper, this ought to be a unambiguous plus for the President-elect.  In practice, matters are not quite so simple.

John McCain, who handed the dossier of allegations about Trump and Russia to the Director of the FBI, has a particularly dire relationship with the President-elect, which is why he reportedly “was reluctant to get involed”.  But is is fair to say that although most American congressmen have not been the target of personal criticism by Trump, as McCain has, a substantial slice of them have a very different view of the world.  They want lower public spending, are socially conservative, and are viscerally hostile to Russia.

Indeed, there is a sense in which Trump is not really a Republican at all.  Before he ran for the party’s nomination this time round, he had a history of donating more to Democrats than to members of the party he now represents.  He also sought the Reform Party’s candidacy for the presidency in 2000.  On some issues, such as tax cuts, he is a recognisable member of the Republican kirk.  On others, such as protection and Russia, his position is unusual.  His campaign for the presidency smacked more of independent populism than recent republicanism.

America’s constitution was created to share power.  The upside is that a President can be restrained; the downside is that he can be hobbled.  Trump’s appointments already pull in different directions.  The fear of the President-elect on the Left is of a strong Trump, rampaging through government as he rampaged through his party’s primaries.  We could instead have a weak one – pursued not only by the security services over his campaign’s links with Russia, but by his own party in Congress too.