Within minutes of entering the White House, Donald Trump had removed pages on the presidential websites referring to climate change. That's it; the global environmental phenomenon that threatens the very future of hundreds of millions of people - deleted.
On Tuesday, as the debate about facts versus the lies dubbed 'alternative facts' rumbled on, Trump - declaring himself an environmentalist - expedited the approval process of the Keystone XL and the Dakota Access oil pipelines.
It is in this context - of Trump standing in total denial of the facts of climate change and of using fear and hatred to divide communities - that the British Prime Minister will become Trump's first visiting foreign leader on Friday.
There's a strong smell of desperation hanging over Theresa May's visit. With Brexit looming, it seems the Prime Minister will do anything to give the impression that a quick and dirty trade deal with the United States can be pulled out of the hat in a couple of years' time; even if that means trading away the regulations that protect peoples' health and the environment, global action on climate change, or even just basic standards of decency and respect. "Britain is open for business" is the mantra - and there is a real danger that this could drown out everything else.
But the Prime Minister's visit also runs the real risk of normalizing the extraordinary events unfolding in the US. At the very least, Theresa May's presence will likely be seen as endorsing the doctrinaire foreign policy that puts 'America First', something that probably will come to mean 'America only'. The chances are, she will do this while having zero influence over Trump's actions.
Simply stated, the Prime Minister should not go. But as May will meet Trump, and as this will almost inevitably provide him with a coat of international diplomatic varnish, then at the very least, she must raise - and raise publicly -the concerns of UK and world citizens.
During the inauguration weekend, another alliance has been forming pan-Atlantic. More than 3.7 million Americans in 500 different cities turned out in the US to march against the Trump administration's abuse of women, people of color, people of different religions, genders and sexual orientations, and the environment. This turnout was mirrored by the hundreds of thousands who marched in the UK's towns and cities, and around the world.
This strength of feeling is inspiring. People from all walks of life and of all colours and cultures took part. The Prime Minister needs to have this reality of a global resistance firmly lodged in her head as she enters the twilight world of 'alternative facts.'
From this, Theresa May can conclude that she has a mandate to stand up for women's rights, the rights of minority communities and, from Friends of the Earth's perspective, the urgent need to protect the environment.
Trump's position is clear. His 'America First' mantra and his early actions are the drawing up of a death warrant for communities around the world. The Prime Minister, and every world leader that visits Trump, needs to convey that the United States becoming a rogue nation on climate change is unacceptable. The lives of entire populations depend on it.
On climate, her message to Trump must be clear and made in public:
First, she must clearly restate the UK's commitment to the UN climate talks, and to the Paris Agreement she and Obama signed in 2015, and say that she will not agree anything on trade with a country that is not part of this process. Trump has said he will pull the US out of Paris.
Second, she must signal her clear disapproval at the unravelling of US domestic climate change policy. A US-UK trade deal will export US pollution to the UK.
Trump has famously said that if US companies seek to offshore production then they will have to pay handsome tariffs to bring those goods back into America. Two can play at that game (and, in trade policy, they invariably will).
Third, Prime Minister May should make it clear that if the US does renege on policies to cut emissions, then US products will have to pay the costs of their dirty emissions at the UK border.
Trump cannot carry out his sweeping 'America first' promise and make trade deals work. May visiting now, before we understand the degree to which he plans on seeing this promise through, is very poor judgement.
But if she is prepared to stand up to Trump and to argue in the name of equality, decency and science, she could appear strong. Rushing to Washington with a tin of diplomatic varnish for Trump will make her and Britain look desperate and weak.
By Craig Bennett, chief executive of Friends of the Earth England, Wales and Northern Ireland and Erich Pica, president of Friends of the Earth US