The World Tonight

With a 6-3 majority, the Supreme Court ruled President Trump exceeded his authority when he imposed tariffs via a law reserved for national emergencies. The president has used Nixon-era legislation to impose new, albeit temporary, tariffs. Also on the programme: the BBC understands the government is considering legislation to remove Andrew Mountbatten-Windsor from the royal line of succession.And we hear from the scientist behind our ‘nature notes’ series. What does the habit of observing the natural world give us in return?