Ooh, that’s a big one,” Donald Trump said Monday as he signed an executive order – one of dozens during his first hours as president – to withdraw the United States from the World Health Organization.

President Donald Trump said on Saturday he may consider rejoining the World Health Organization, days after ordering a U.S. exit from the global health agency over what he described as a mishandling of the COVID-19 pandemic and other international health crises.

Public health experts say U.S. withdrawal from the W.H.O. would undermine the nation’s standing as a global health leader and make it harder to fight the next pandemic.