Why is the US quitting international organisations?

There are yet more signs that the US is disengaging from the global order established after World War Two. President Donald Trump has ordered his administration to pull out of more than 60 agencies, half of them part of the United Nations. Trump argues that being member of these organisations is contrary to his country's interests. The Secretary of State went as far as saying they're useless or wasteful. This move has prompted global outrage, with the UN saying its 'responsibility to deliver’ will not waver. So, where does this all leave the multilateral global order?