"I apologise it was taken that way. I was with a group of friends and there was nothing serious about it.”

Haven’t we heard that enough by now to know that’s a pathetic, bullshit excuse? What you say with friends reveals something about you and how you think. The guy could’ve said nothing and he’d have been fine, but for some reason the idea of taking over Iceland was in his mind and for some reason he felt comfortable making light of it. If infringing on another country’s sovereignty is such a non-issue that he feels comfortable joking about it, he’s clearly not fit to be an ambassador. (Though as a Trump-appointee, it’s hardly surprising he’s not fit for the job.)