With US President Donald Trump moving the US towards tightening sanctions on Iran, and the tweet-happy leader threatening war with North Korea, at least one country is seeing the noose of US sanctions loosen.

Washington this week made permanent the lifting of key sanctions on Sudan after a nine-month period during which they had been temporarily put on hold.

The Trump administration has adjudged that Khartoum has met the five criteria laid out by his predecessor Barack Obama in January to...