So with a great (self-trumpeted) fanfare, the Greens have returned to the climate-change debate — and about bloody time.

Many on the left, including some of the deepest green, had been shocked and dismayed at their intransigence during the past year, and in particular at its chaotic conclusion.

From the very beginning Senators Bob Brown, Christine Milne and their three colleagues rejected the government’s agenda out of hand. It was, they insisted, a worthless travesty of what was really required — a pusillanimous and inadequate response to a worldwide crisis.

Well, from a rigorous scientific point of view, they may well have been right; but politics has never been a rigorous, scientific business. It is the art of the possible, about least worst solutions achieved through compromise, a word that the Greens have always considered obscene to the point of blasphemy.

Prime Minister Kevin Rudd’s approach was a long way from perfect, but it was a start, an attempt  to ease the nation into a new and often unpleasant way of life. His calculation, reinforced by the best research available, was that the public simply would not accept the radical tactics favoured by the Greens, or even the more-considered measures suggested by his own chief adviser, Ross Garnaut.

He wanted to achieve at least a rough consensus, not only among the voters, but among the major stakeholders. That meant bringing everyone, including the polluting industries, inside the tent. Of course, there would always be recalcitrants, but as long as they could be portrayed as a perverse or self-seeking minority, there was a good chance of progress. Above all, he wanted political bipartisanship, which was why his final Bill was very similar to the outline John Howard had taken to the electorate in 2007.

And he very nearly succeeded; right up until the last gasp it appeared that Malcolm Turnbull could deliver enough senators to pass his Emissions Trading Scheme and thus lock the foundations for real change into place. But the Greens wanted no part of it. They now say they were always open to negotiation, but their starting point was a target that would have strained the limits of many in the Labor Party, much less the coalition.

And in any case, the hard fact was that the Greens could not offer Rudd what he needed; the numbers to get the Bill — any Bill — passed. There were only five of them; Rudd needed seven. Any formula that would satisfy the Greens was bound to be opposed by the Liberals, even under Turnbull, and the National were already off the planet. Thus Rudd would have needed both independents. Conceivably Nick Xenophon might have been open to persuasion, but Steve Fielding was a hopeless case. Rudd’s only hope was the Liberals, which meant more compromise, not more bravado.

Ironically, even after Turnbull was rolled, the Greens could still have saved the day: two Liberals were prepared to cross the floor, and if the Greens had seized the moment, as many of their supporters urged, a flawed but basic ETS would have become law; the foundation for more determined action would be in place. But the Greens preferred to preserve their ideological impregnability, and delivered precisely nothing. As Gough Whitlam was fond of remarking, the impotent are always pure — and, he might have added, frequently vice versa.

But it now seems that Brown and Milne have had a Damascene conversion to reality: they are now proposing what they describe as an interim scheme to break the deadlock. The idea is a two-year price on carbon of $20 per tonne, with the proceeds spent on incentives for alternative energy and on compensating low-income households — but not the polluting industries, who would receive free permits under the government scheme.

This is in line with the original Garnaut Report, and therefore has a certain credibility. But it is undeniably a compromise — even the Greens don’t claim it would  do much to reduce the actual rate of emissions. The best they predict is that at least it might stop them from increasing, and perhaps, just perhaps, bring them down by a percentage point or two. This is a long way behind the government’s own minimum target of 5% reductions, about which they have been so contemptuous. But it would, as they say, be a start.

Unfortunately all the old political constraints still apply; in the present senate a Labor-Greens alliance is still two votes short of a majority. Tony Abbott has totally rejected the idea of any form of tax or levy on carbon, but interestingly he did not dismiss the idea immediately. And given that it now appears that even the January 31 deadline for emissions targets set at Copenhagen is not to be taken seriously, the Green proposal is just about the only concrete proposal for action on the table.

So thanks, Senators Brown and Milne — and welcome back to the real world. Who knows, you might even like it here.

Apart from the fact that he appears to have lost his chin in an unfortunate breeding accident, Prince William seems a pleasant enough young man; and since (for once) we are not paying for his royal flash-through, there is no reason to be unkind about him.

But equally, there seems no reason to cringe, grovel, kowtow or otherwise abase ourselves, which the media have done in a particularly unedifying fashion. His personable appearance is utterly irrelevant to the republic debate: if he were a slithering, gibbering, bug-eyed monster he would still be second in line to become our head of state, and there is absolutely nothing we could do about it.

And that’s the point. Like any other form of autocracy, the system of monarchy is only as good as the worst person who can become monarch. On January 26, India celebrates Republic Day. We celebrate becoming a British penal colony. Guess who wins?