The most egregious example was Trump's cancellation of the multi-national Iran nuclear treaty that had been welcomed by the world as a major step to Mideast denuclearization.
In abrogating the international treaty signed by the US, Britain, France, Germany, Russia and China, the US humiliated its allies and rivals who were strongly in favor of the accord. Iran had already handed 97% of its enriched uranium to Russia, shut down reactors and centrifuges, and allowed UN inspectors to run all over its nuclear facilities when Trump tore up the deal that had been under negotiation since 2015.
Iran has been under a harsh US-led trade embargo since its 1979 revolution that was designed to cripple its economy and military and drive the people to rebel against their government. Washington used the same tactics – without success – against Saddam Hussein's Iraq and Fidel Castro's Cuba.