In all of the sound and fury and sordid events that led to the resignation of the British ambassador to the US, Kim Darroch, there has been little attention paid to the question of what is the function of the UK ambassador in the US, or indeed, that of Ambassadors anywhere.
In a past without modern communications, media, or a 24 hour news cycle, picking up intelligence from a host country and passing it back to the home country was perhaps the most important part of the job. Any serious advocacy would be done by the head of state; an Ambassador merely paved the way as a sort of glorified front man. They were traditionally quite limited in what they could do and the risk of free lancing meant that successful Ambassadors rarely deviated from their talking points.
But the world has changed, and it is not enough now to be merely a listening post. Indeed, even as a listening post, embassies must be careful who they listen to. Just as the old world of a handful of elites firmly gripping the levers of power has fallen apart, so embassies must get ahead of coming trends in order not to be engulfed up by them. They must constantly challenge the received wisdom of the elite echo chambers and try to get beyond them. This is especially true in the US, and it is not just Donald Trump who has brought this reality to the fore.