In an increasingly complex and fractured international system, the norms and expectations of how nations and markets interact is changing from one era into the next before our very eyes. 

That is the main focus of inquiry for Gary Gerstle, whose new book, "The Rise and Fall of the Neoliberal Order: America and the World in the Free Market Era," chronicles the 50 years of primacy of neoliberal thought in American politics before crashing onto the rocks of new ideological movements with the emergence of Donald Trump-style authoritarianism and Bernie Sanders-style anti-capitalism.

In this conversation with Robert Amsterdam, Gerstle, who is the Paul Mellon Professor of American History at the University of Cambridge and the winner of the "Book of the Year" by the Financial Times, explains that not everything that happens in politics can be understood in short election cycle periods, but instead we should be looking at the overall conceptions of political economy and the order these beliefs sustain.

Pointing to continuities of these orders, such as Eisenhower carrying on the New Deal system and Bill Clinton carrying forward with many core assumptions about trade inherited from Reagan, Gerstle argues we are in a moment of fragility and uncertainty, as once marginal voices in Sanders and Trump have now entered the mainstream. We are without a political order currently, and neither is democracy in a healthy state of competition, so what shall emerge next is unlikely to look similar to the past, as both left and right have lashed out against the free movement of capital, free movement of people, and both have different ideas of the role of the state in economic and social affairs.