As a former politician, I have often lamented the journalistic tendency to treat politics as a matter of personalities rather than policies. But there are times when political personalities - and their interaction - can provide an insight into what is really happening.
Just four months into his second term, it is already apparent that the Prime Minister is a very different John Key from the one we learned to know and (at least for some) love in his first term. The relaxed and amiable friend to everyone has - as John Armstrong has pointed out - somehow transmogrified into a tougher and much less accommodating political leader. The whole tone of the Government's approach is now very different.
The John Key of the first term showed a remarkably accurate sensitivity to popular opinion. He avoided controversy wherever possible and built an enviable popularity by unerringly identifying where the political centre of gravity on any given issue could be located.
Today, however, we see a different attitude from the Prime Minister. He is obviously now committed to an agenda that is increasingly likely to encounter opposition and controversy. He seems determined to pursue that agenda - for example, on asset sales - whatever public opinion may have to say.
If the prime ministerial smile was the defining image of his first term, the second seems destined to be characterised by the prime ministerial shrug - a shrug that seems to say that he is determined to do what he wants, whether popular or not.
What explains this sudden and apparently inexplicable change?
What is now clear is that the goal of the first term was simply to win the 2011 election. The key to achieving that goal was to be the Prime Minister's personal popularity - particularly with the politically uncommitted.
That goal having been achieved, a quite different goal has now been identified. A Prime Minister who was criticised in his first term for being lightweight and not making a difference seems now to have set himself the task of making his mark and leaving a political legacy.
The second term, it seems, will be used to push through an agenda of change which may commend itself less - or not at all - to the uncommitted, but which will deliver to the Prime Minister's own closest supporters much of what they elected him to do.
It is, in its own way, quite refreshing to see a politician who sees the exercise of power, not as an end in itself, but as the means by which real change is to be brought about.
But the Prime Minister's change of focus warrants scrutiny on other grounds as well.
If his goal is to use power now rather than merely prolong it, that inevitably suggests that he does not see his premiership extending beyond the next election. He has given hints in the past that he does not see himself devoting the rest of his life to politics; his apparent determination to go for broke now is the best evidence we have that he sees two terms as Prime Minister as being quite enough.
That, in turn, means that picking up the pieces after the next election - whatever the outcome - is likely to be the responsibility of someone else.
And that brings into focus the second major piece of evidence to support the proposition that we might be looking, in 2014, at a post-Key era - the likelihood that a similar thought seems to have occurred to some of those who might see themselves as being in with a chance of succeeding John Key, when the time comes, as party leader.
The most obvious contender might seem to be Bill English - the Deputy Leader, and of course supported by a significant group of MPs who have already had success in projecting him into the leadership on a previous occasion. But there are growing signs of tension in the relationship between Key and English. There have been several recent instances when the two men have said - it seems quite deliberately - quite different things, to the point of embarrassing or directly contradicting the other.
Take, for instance, Bill English's startling admission that the estimate of the proceeds from asset sales was "just a guess" - something that no politician of his experience would have allowed himself to say by accident, and certainly not what John Key would have expected from a loyal deputy committed to this central element in Government policy. And look at the direct disagreement this week between Key and English on the issue of whether a renewed boom in house prices is getting under way.
These tensions do not arise by accident. The signs are that Bill English may know, or think he knows, about John Key's plans for 2014, and may be distancing himself from his leader so as to offer a fresh start when the time comes.
Or, he may sense that there are other plans afoot. He will have noticed with apprehension the rise of Steven Joyce, and the new Minister for Everything's closeness to the leader. There is nothing more guaranteed to engender a sense of angst than the sight of a rival being promoted. Watch this space!