Presidential primaries – the circus that has traditionally wended its way from Iowa to New Hampshire and beyond every four years -- is one of the most distinctive features of American political life. From the insurgent campaigns of Jimmy Carter in 1976 to Barack Obama in 2008 and even Donald Trump in 2016, primaries have enabled the rise of politicians who could never have succeeded under the old boss-controlled system. US political parties are private organisations albeit without the formal membership of parties in other countries, yet their candidate nomination process is regulated by state law. So, how, why, and when did US political parties come to choose their presidential candidates in this way? How have primaries shaped elections and the trajectory of politics? And in a year in which both parties appear set to nominate unpopular candidates, does this reflect the failure of this system for presidential candidate selection? Adam talks about these issues with the leading historian of modern US politics, Professor Julian Zelizer of Princeton University, a CNN contributor and author or editor of fifteen books on political history.   Hosted on Acast. See acast.com/privacy for more information.