“A crime against humanity.” Richard Horton, the editor of The Lancet, spoke for many when he condemned the decision by President Trump to cut US funding to the World Health Organization, in the midst of a pandemic that has infected an estimated 2 million people, more than 137,000 of whom have died. Trump’s disdain for international agreements is well known. In 2017 he pulled the United States out of UNESCO and the Paris climate accord. The following year he withdrew from the Iran nuclear deal. These departures take the United States even further outside the international system. It is already missing from the list of countries that have ratified some of the most important international agreements, including conventions on torture, discrimination against women, rights of the child, and landmines.

'Crime against humanity': Trump condemned for WHO funding freeze Read more

Until now, world leaders have adhered to diplomatic protocol, avoiding anything but the mildest public criticism of this notoriously sensitive president. Their true feelings are only revealed when their private conversations are accidentally overheard. This time it’s different. Simon Coveney, the foreign minister of Ireland, a country with exceptionally close ties with the United States, described Trump’s decision to cut funds to WHO as an “indefensible decision, in midst of global pandemic. So many vulnerable populations rely on WHO – deliberately undermining funding and trust now is shocking.” Heiko Maas, the German foreign minister was slightly more restrained, tweeting that: “Blaming does not help. The virus knows no borders”. In the UK, however, where ministers are still hoping for a post-Brexit trade deal, a Downing Street spokesman rejected an invitation to join the condemnation, although they did voice support for the WHO.

Why undermine the organisation that is at the forefront of responding to a pandemic? For Trump, this seems particularly illogical – the pandemic has already killed more than 30,000 Americans. The answer is simple. In the midst of an election year, with his approval ratings falling, Trump needs to find someone else to blame. Now that the daily White House briefings have taken on the role of campaign rallies in locked down America, nothing can be allowed to undermine the narrative that he is the saviour of the American people. Failings are the fault of others. Once it was the Mexicans (ironically, Mexico is now restricting Americans from entering the country). Then it was China, whose political leaders Trump considers insufficiently obsequious. Now, he has redirected his ire at the WHO.

It hardly needs to be said that Trump has justified his decision with claims that fail to withstand the most basic scrutiny. He claims that the WHO was “severely mismanaging and covering up” the early stages of the pandemic, thereby delaying the response by the United States. Yet the WHO had warned of person-to-person transmission as early as 23 January. Six days later, his economic adviser warned of the possibility of hundreds of thousands of American deaths. Trump ignored them both.

The decision will clearly damage the WHO. First, there is the loss of funding. As the world’s richest country, the United States contributes 40% of the WHO’s core budget, although this only amounts to 20% of its total spending. The US also contributes the largest share to the remaining 80% of voluntary contributions.

The US theoretically contributes roughly 10-15% of the WHO’s budget as its largest contributor. It’s uncertain whether Trump can legally block payments to the WHO’s core budget, as these are authorised by Congress, but he could stop those voluntary payments made by federal agencies such as the Centers for Disease Control.

With a total contribution of a little under $900m, roughly what the NHS spends in 36 hours, other countries could step up to the mark to replace at least some of this shortfall. However, the decision will likely have a disproportionate effect on areas where the United States has made substantial earmarked contributions, such as polio eradication. More importantly, this is a massive distraction for an organisation working flat out to tackle one of the most serious threats to the health of everyone, including Americans, in decades.

The Covid-19 pandemic has exposed the weaknesses of individual leaders and international cooperation. In a world where Jair Bolsanaro can threaten the world by allowing the Amazon to burn, or Donald Trump can undermine those leading the response to a pandemic, the need for a new international order has never been more urgent.

• Martin McKee is professor of European public health at the London School of Hygiene and Tropical Medicine and an adviser to the World Health Organization