Donald Trump’s travel ban has caused huge controversy within the United States and uproar on this side of the Atlantic too.
It has put Theresa May in a difficult position, after she so publicly attempted to forge a strong personal relationship with the new US president.
The ban is one of a number of measures that Mr Trump has sought to introduce soon after taking office, in a bid to repudiate the essence of Barack Obama’s presidency.
That Mr Obama broke with convention and not merely criticised a successor as president, but did so days after he left office, is an indication of the scale of the anger in the American establishment towards Mr Trump’s approach. The fact that a respected conservative political leader, Paul Ryan, the Republican Party speaker of the House of Representatives, has referred to bumps in implementation in the policy is a sign of unease even in the leadership of Mr Trump’s own party.
Yet for all this, a number of points are worth bearing in mind. The policy, according to an opinion poll of Americans yesterday, has a clear margin of support among the US public. That does not make it inherently OK, but it is a reminder of the fact that this is a policy of a president who was outspoken about his plans during his election campaign and went on to win.
Also, there is a problem in the opposite direction in much of Europe – a refusal to so much as mention Islam and terrorism in the same sentence. America experienced the almost unbelievable horror of 911 and it will not tolerate terrorism in the way that we in Northern Ireland have been forced to do.
There are questions about whether this ban is morally acceptable, whether it can work, why it was extended to some countries and not others and whether it will just inflame feeling. But some of the reaction in Europe has been hysterical.
It does seem that Mr Trump was offered a state visit to Britain rather fast. But it would be absurd to ban a visit from him having had such visits from countries including China, which have much worse human rights record than America.