WASHINGTON - The disappearance - and very possibly the gruesome murder - of Saudi journalist Jamal Khashoggi, at the hands of the Saudi state, presents a quandary for the Trump administration, and also a watershed that is being closely watched by the rest of the world.

Failure to hold a government to account for the enforced disappearance of a person because that government is an ally, and - as US President Donald Trump has mentioned more than once in recent days - buys billions of dollars worth of military hardware from the US, may be a cynical exercise in realpolitik at one level, but at another will send a signal to other governments around the world as to how much they can potentially get away with.