Chris Bertram said yesterday:

When David Cameron announced that the Tories would reduce net migration to "the tens of thousands" it was obvious to anyone remotely well-informed that the policy was (a) bound to fail and (b) attempts to implement would result in illiberal nastiness on an unprecedented scale, divided families, stigmatization of minorities etc. Yet I don't recall broadcasters asking tough questions, treating him with derision etc. And this was a policy likely to be implemented by a party with a serious chance of power. Compare this with the snorting incredulity with which broadcasters treat, say, the Greens. It is almost as if those with a lower chance of power are held to higher standards of argument and evidence.

His point generalizes way beyond immigration policy. Whilst broadcasters seem obsessed with the non-existent "costs" of opposition policies such as housebuilding and cuts in tuition fees, they have grotesquely understated the costs of fiscal austerity.

The issue here isn't simply a partisan one. Mr Cameron has betrayed a confidence of the Queen; jeopardized the union: presided over a diminution of Britain's role in world affairs and kowtowed to the neo-racist far right. In all these respects he should have earned the contempt even of conservatives.

And yet this is not how he is portayed in the media.Why not?

The answer is only partly due to the economic illiteracy of mediamacro and bubblethink; these don't explain the easy ride Cameron has had in other policy areas.

Nor is it simply due to right-wing tribalism. For one thing, John Major was regularly portrayed as weak and incompetent - despite perhaps possessing more estimable personal qualities than Mr Cameron. And for another, leftists misdescribe Cameron. Even hostile cartoonists typically picture him as a heartless toff rather than a hapless sap who is out of his depth. And even even our most "leftist" newspaper can ask: "has Ed Miliband got what it takes to be Prime Minister?" without noting that the standard is now so low that any reasonable person could meet it.

Instead, I suspect that what we're seeing is simple deference, in two different senses. One is that Cameron's background, if not his conduct, means he is "officer class" material. He looks like a Prime Minister, even if he doesn't act like one.

The other is that, simply by virtue of having succeeded in acquiring power, Cameron attracts admiration. This is not just true for political reporters: just look at how football reporters have cringed supinely towards Alex Ferguson and Jose Mourinho. Adam Smith described the media - including the BBC - beautifully 255 years ago:

We frequently see the respectful attentions of the world more strongly directed towards the rich and the great, than towards the wise and the virtuous. We see frequently the vices and follies of the powerful much less despised than the poverty and weakness of the innocent.