Common climate in Canberra and Washington
Turn the clock back four years, and you could not have slipped a cigarette paper between the climate policies of the administrations in Washington DC and Canberra.
With the election of Kevin Rudd in December 2007, paths diverged.
Against the backdrop of opinion polls showing climate change as a major concern for Australians, Mr Rudd's Labor government ratified the Kyoto Protocol, unveiled new targets for cutting carbon emissions and announced that a new emissions trading scheme (ETS) would be the principal vehicle for reaching those targets.
A year later, Barack Obama entered the Washington White House, talking a positive game on the issue but making clear his desire or even his need for legislation to proceed through both Houses of Congress, and maintaining his opposition to re-entering the Kyoto fold.
Now, there's a case for arguing that the old days are back, and that Canberra and Washington are once again in step.
Mr Rudd no longer holds the reins of power, having been deposed as Labor leader and prime minister in a bloodless coup by his former deputy Julia Gillard - at least, until the forthcoming election.
There were many reasons for Mr Rudd's fall, but one was that voters were dismayed by his plans to weaken and delay advent of the ETS.
Ms Gillard was expected to - indeed, had hinted that she would - restore the fully-fledged measures that Mr Rudd had watered down.
Now, she too is being accused of dilution. In a televised pre-election debate that my colleague Nick Bryant has written up, she shrank from restoring the full ETS scheme and instead proposed setting up a "citizens' assembly" on climate change.
There's an argument that, like committees everywhere, it would simply kick the issue into the long grass. And that's exactly how it's being perceived by swathes of the Australian electorate, according to some analyses.
Meanwhile in the US, there's been a deal more cogitating over the causes and effects of the Senate Democrats' decision not to push for a full climate bill during this session, as mentioned at this blog last week.
Ross Douthat in the New York Times argues that for all the finger-pointing that's going on, there's one analysis that makes sense:
"If their bill is dead, it was the American conservative movement that ultimately killed it."
In his book, there's a strong case for saying the conservative movement was correct to do so and that inaction is actually the wise course.
That's not the message, however, coming from the latest look at the US electorate.
"Our surveys reveal a small decline in the proportion of people who believe global warming has been happening, from 84% in 2007 to 74% today..."
...says Jon Krosnick of the latest in a series of polls conducted from Stanford University.
Whatever the reason for the decline - and Mr Krosnick cites figures showing cold weather in heavily-populated parts of the US was behind it - 74% still represents a pretty sizeable majority.
Against this background, you might expect that activists in favour of climate legislation would be mightily miffed by last week's abandonment.
Not a bit of it, according to an analysis in The Hill, the Washington political website. Activists were so disappointed by what they saw as the limited scope of the Kerry-Lieberman bill, the latest version of the draft legislation, that some at least are saying "good riddance".
"Given that the energy bill was already a big capitulation to polluters, the failure to move it will not exacerbate the enthusiasm gap that was already there due to its underlying lameness..."
...says Adam Green, co-founder of the Progressive Change Campaign Committee.
The problem facing Mr Green and his counterparts in Australia is this: given that their regimes are both failing to deliver what the public apparently wants, despite all the groundwork they had put in and despite all the rhetoric that has been spouted, what can they do to make sure regimes do deliver anything more than words once they eventually get into office?
In both societies, some might argue that the tipping point is easy to identify: that it will come when climate change is a big enough electoral issue that leaders are prepared to take on powerful business lobbying once they actually attain office.
But that's to ignore a simple reality. Both nations have bipartisan politics, which tends to drag parties and leaders towards the middle ground.
Once again, then, not a cigarette paper between the two nations. Once they stood together to destroy the Kyoto Protocol; now their leaders are talking a greener game, but still failing to deliver what their electorates say they want.
And in both countries, proponents of climate action are scratching their heads and wondering what to do about it.