multilateralism

noun2

1. •
   Unbiased trade between nations, in contrast to bilateralism.
2. •
   A system by which nations consult others in matters of foreign policy, by way of organisations such as the United Nations.

   • Trump’s national security adviser, John Bolton, a lifelong opponent of multilateralism and its institutions, had pushed for a hardline position, particularly on the role of the IMF. — 2018