Donald Trump wants to take Greenland - and the White House has confirmed that all options are on the table, including the use of force.
While a military operation is just one of a range of economic and political options being considered, since it would be an attack by one Nato member on another, such a move would represent a nightmare scenario for the Nato alliance, and likely an existential one.
Trump has repeatedly said that Greenland is vital to US national security, claiming without evidence that it is "covered with Russian and Chinese ships all over the place".
With the expertise of US, British and Danish experts, we consider the various options the president may be looking at, and the possible justification for each one.
Defence analysts say that a lightning operation to take Greenland could be done relatively easily, but the fallout would be monumental.
