Representing New Zealand with grace, dignity and authority is very much part of the Prime Minister's job.
It is the sad fate of leading politicians in a democracy to be heartily disliked, whatever their personal merits may be, by a substantial proportion of the voting public. That is as true of John Key as it was of his predecessor, Helen Clark.
It is not usually the case that it is the personal qualities of the political leader that are at issue, although those who disagree with a politician will often project their political opposition on to the supposed personal deficiencies of the object of their hostility.
But in most cases, even in the case of a political opponent, people are quick to close ranks when it comes to supporting a political leader, particularly a Prime Minister, as a representative of our country overseas. Whatever the controversies and disputes domestically, most of us want to see our Prime Minister performing with distinction and earning respect when it comes to the international arena.
I recall an occasion when I had the privilege of being present when Helen Clark, as Prime Minister, met leading members of the Chinese Government.
Some members of the New Zealand delegation would almost certainly have been opposed to the Prime Minister in terms of domestic politics (and even I did not agree with her on some issues), but we were all impressed with the way she conducted herself, and proud of the obvious respect in which she was held by her hosts.
Even on those occasions when she said something she perhaps later regretted - as on the occasion when she suggested that, if Al Gore had been US President, there would have been no Iraq invasion - it was on an important issue on which she was entitled to hold a well-considered opinion. The standing she enjoyed in international terms was confirmed, of course, when she was offered the UN's third most senior post in 2009.
It is therefore disappointing that John Key, whatever his other qualities, has not projected an image overseas of which we can be equally proud. He is beginning to establish something of a reputation in the international media as someone who is at best not to be taken very seriously and at worst prone to gaffes.
His gratuitous and rather coarse insult concerning David Beckham was hardly serious enough to cause a diplomatic incident but it did receive worldwide coverage and made front-page headlines in some British tabloids - and it is, sadly, the case that the person who came out of the episode with damage to his reputation was not David Beckham but the New Zealand Prime Minister.
This minor misjudgment may not matter much in itself, but it may be symptomatic of an increasingly casual and flippant attitude taken by the Prime Minister to the responsibilities of his job. On the same day as the Beckham comment, John Key - presumably in an attempt to show that he was "one of the boys" - ventured an ill-judged "joke" (this time on New Zealand radio) that managed to use the word "gay" as an insult.
The increasingly numerous "brain fades" that John Key has suffered in recent months, and the number of times that he has shuffled off responsibility on to other agencies when his government has been found at fault also suggest a political leader whose mind is not entirely on the job.
And it is of course disappointing that when he is occasionally reported in the international media, his profile is so indistinct that he has in recent times been described as "David" and "Geoff" Key , or as John "Kay" or John "Keys" - clearly not someone who is making a big impression.
"So what?" will be the response of many of his supporters. Who cares what foreign journalists make of him, so long as he is doing a good job for the people at home? But representing New Zealand with grace, dignity and authority at international gatherings is very much part of his job, and the country suffers if it is not done well.
As a small country, we are in more need than most of a leader who can punch above his weight.
The suspicion must be that John Key, by preference and temperament, sees himself more as a populist domestic politician - a role where his lapses matter less and are more easily forgiven - than as a serious international figure. It may even be that he is someone who is more attracted by popularity than power.
But do we really want a Prime Minister who would rather be Paul Henry?
Bryan Gould, former vice-chancellor of Waikato University, was previously a British Labour MP.