The latest flirtations of the US political right with "climate denial" look set to marginalise the country even further within the global community of nations - at least when it comes to climate change.
Does the US risk isolating itself from the global community?
With a majority in the House of Representatives, politicians unconvinced of the case for action on climate change have been able to attack the edifices of climate science and international negotiations in quite dramatic ways.
Budgetary measures passed by the House at the weekend would not only withdraw US funding from the Intergovernmental Panel on Climate Change (IPCC) - they would also end financing for the office occupied by Todd Stern, the experienced official who leads US diplomacy within the UN climate convention (UNFCCC) and other fora.
Before these measures could come into law they would have to make it through the labrynthine processes that precede a US budget agreement, including being approved by the Democrat-controlled Senate and signed off by President Obama.
So, you might conclude they'll never make it.
Equally, remembering that they'll be relatively minor ingredients of a vast budgetary package whose negotiation will require extensive horse-trading, it's easy to see how they might make it through these various hurdles if the Democrats judge they're more expendable than other items.
The claims used to back the proposed IPCC cuts are easily countered. Launching his "de-funding" amendment, Congressman Blaine Luetkemeyer described the panel as:
"...an entity that is fraught with waste and fraud, and engaged in dubious science..."
"...leading global scientists intentionally manipulated climate data and suppressed legitimate arguments in peer-reviewed journals. Researchers were asked to delete and destroy e-mails so that a small number of climate alarmists could continue to advance their environmental agenda."
The IPCC has never been found fraudulent by any investigation - indeed, successive reviews, notably by the InterAcademy Council, have found just the opposite.
That being so, to make the allegation outside the legal protection afforded by the political process would potentially lay the speaker open to action for defamation.
Neither has it been shown that UEA scientists intentionally manipulated data - again, the opposite conclusion is eminently more defensible - nor that they had an "environmental agenda".
While criticising proponents of climate action for basing their policies on dodgy ground, Mr Luetkemayer apparently had no problem making allegations demonstrably lacking a factual basis.
You might also ask where the notion of consistency has gone, given that when Sarah Palin's e-mail account is hacked, the Republican party condemned it as "a shocking invasion of privacy and a violation of the law" whereas the same entity apparently brings no criticsm of the hacking of CRU servers.
Nevertheless, this is politics - and facts have always proven to be malleable in that particular furnace.
So what would these measures mean if they all went through?
The IPCC sums are minimal - about $3 million per year. A large proportion goes to fund the Technical Support Unit (TSU) for IPCC Working Group 2 - the group on impacts, adaptation and vulnerability, one of the three principle strands of IPCC research.
As the group currently has a US-based co-chair, Chris Field from the Carnegie Institution at Stanford University, the US gets to fund the TSU - the small team that supports the scientific assessment.
With the money gone, the TSU would either have to find another source of funding - which might not be too hard in a US awash with charitable foundations signed up to the need to curb climate change -or, more provocatively, move to Argentina, home of the group's other co-chair, Vicente Barros.
IPCC working groups always have one co-chair from a developed nation and one from a developing country, and the richer partner has always hosted the TSU - which in some peoples' eyes has given too much priority to western concerns.
A switch to the poorer partner - and Argentina is surely rich enough to host a TSU if it wanted - would be a new tweak and one that would reduce US influence over the IPCC's next report.
The House's budgetary bill seeks to lop far greater sums from the climate science budgets of US agencies such as the National Oceanic and Atmospheric Administration (Noaa).
Cuts along these lines would also weaken the US voice as its dominance in climate research waned.
Putting Mr Stern's office off-line, meanwhile, would significantly curb US influence within the UN climate negotiations.
Critics say its main role recently has in any case been to stall and weaken... but it has been engaged, and undoubtedly highly influential.
At the recent Cancun summit, Mr Stern's delegation implacably fought for and won on a number of points - notably securing World Bank influence over international climate finance in the teeth of vehement opposition from developing countries.
There would surely be a risk that trimming the US presence in the UN process would weaken its capacity to influence such matters.
Mr Stern and his deputy, Jonathan Pershing, have stuck to the line that the US administration will not sign a treaty that the Senate will not ratify. Recently, they've suggested that for now, governments should stop looking for a global deal and concentrate on delivering the unilateral voluntary pledges they made around the time of the Copenhagen summit.
This - though undeniably realistic, given the way political winds are blowing in the US - is also leading some movers and shakers in the UN climate process to question whether they should plan for an immediate future that explicitly leaves the US to one side.
A strategy could be adopted that basically ignores the world's biggest economy - though, of course, leaving a window through which it could re-enter if and when the political winds change.
How this might work and what some of the alternatives are I'll return to in another post.
All of this must be galling for Mr Pershing, especially.
"The Bush administration has avoided significant climate change policy, leaving the US so far a largely ignored observer at these international negotiations... The US holds the key to a succesful global climate change treaty."
Current events suggest the political clock may be turning back faster than anyone thought possible when Barack Obama swept into the White House pledging "global leadership" on climate change.
This time, however, the political landscape is different; and perhaps the US doesn't any longer hold the key to a treaty.
No longer is it the world's biggest emitter. No longer is it the most powerful political entity on the scene - that role has been taken by the BASIC group (Brazil, South Africa, India and China).
And climate science - despite Mr Luetkemeyer's interpretation - has hardened, with real-world changes that look very like the signatures of greenhouse warming being registered from the Arctic to the Amazon heightening the concerns of vulnerable nations.
Will the rest of the world wait for the US again - as it did in Copenhagen - especially when its political leaders are apparently bent on downgrading its importance in the climate arena?