Next move - China
It would also hugely affect the relatively unified approach to climate change on display among world leaders at COP26.
"Everything that Biden pledged, led to this relatively good atmosphere and a sense of momentum in Glasgow," said Dr Joanna Depledge, a fellow at the Cambridge Centre for Environment, Energy and Natural Resource Governance.
"But these were just promises, he needs to get the bill through Congress. And it's now looking increasingly dicey. He can do some things with executive orders, but that certainly isn't the kind of sustained institutional climate legislation change that we're really looking for."
"I think the situation to us, is critical."
The despair among many in the US over the possible failure of President Biden's bill will also have knock-on effects throughout the world. This will certainly be the case in China, a country smarting from the perception that it flexed its political muscle in Glasgow to get its way. Biden's political difficulties with the bill are seen as more evidence that the "West is declining".
I am worried 2022 will see a fuller display of geopolitical tension dominating the climate agenda," said Li Shuo, from Greenpeace East Asia.
He is also concerned that the mooted introduction of carbon taxes on imported goods into Europe could elevate a sense of unfairness and frustration in Beijing.
"The Chinese side will see how they are treated vis-a-vis others and make its judgment on whether the game is fair, and most importantly, if it is about the environment at all, or just geopolitics and trade," he told BBC News. Overall, I am looking at a more turbulent year ahead. The years before the Paris agreement were an example of geopolitics helping the climate agenda forward. What lies ahead may be the opposite."
This pessimistic outlook is echoed by the fact that next year's COP is being held in Egypt, and the one after that in the United Arab Emirates (UAE).
"Neither of these countries could be described as climate leaders," said Prof J Timmons Roberts from Brown University in Rhode Island, US. The good side is that COP27 will be in a developing country, and some issues like loss and damage [who pays for the impact of climate change in the worst affected countries, and how it is paid] may get more traction, but on the issue of emissions reductions, it's not clear that they're going to be leaders."
Another key concern heading into 2022 is that some countries may simply ignore aspects of the Glasgow climate pact that they don't like.
One key measure in the deal was the request for all countries to "revisit and strengthen" their national climate pledges by the time delegates gather in Egypt late in 2022.
Despite agreeing to this, a number of countries now say they simply won't update their plans, among them Australia and New Zealand. New Zealand's climate minister James Shaw told national media that this provision really only applied to large emitters like India, China, Russia and Brazil which hadn't significantly strengthened their plans in time for Glasgow.