The future of NATO has been called into question by Donald Trump, if US allies fail to help reopen a key shipping lane in the Middle East.
Iran has effectively closed the Strait of Hormuz - a crucial route for global supplies of oil and gas.
The US President says "its only appropriate the beneficiaries of the Strait help to make sure nothing bad happens there."
But Dr John Strawson, a law professor specialising in the Middle East, says Donald Trump's exact plan isn't clear…
IN: "It's not just…"
OUT: "...planned military operation."
DUR: 0:36