In September 2016, nearly two months before the then-presidential candidate Donald Trump's election, United States President Barack Obama spoke at the United Nations General Assembly (UNGA). "As I address this hall as president for the final time, let me recount the progress that we've made," he said, "A quarter-century after the end of the Cold War, the world is by many measures less violent and more prosperous than ever before …" But with millions displaced worldwide, unresolved conflicts from Yemen to Syria, Iraq to Afghanistan, and armed groups like ISIL (ISIS) and al-Qaeda launching attacks against civilians, was Obama's speech too optimistic? And in the years since, how has US foreign policy changed under President Trump? And what should have been done differently? Samantha Power served at the US ambassador to the UN from 2013 to 2017. As Obama's top UN diplomat at the time, she was responsible for securing international consensus on a variety of pressing issues at the UN Security Council (UNSC) and the UNGA. To discuss the Trump presidency, the difference between Trump and Obama's responses to global health crises, and China's increasing influence on international organisations, she talks to Al Jazeera. - Subscribe to our channel: http://aje.io/AJSubscribe - Follow us on Twitter: https://twitter.com/AJEnglish - Find us on Facebook: https://www.facebook.com/aljazeera - Check our website: https://www.aljazeera.com/