• Sam Rosenfeld

    Assistant Professor of Political Science

    Colgate University

  • Biography

    Welcome! I am an Assistant Professor of Political Science at Colgate University. I have a PhD in History from Harvard University and study parties and American political development. My research interests include the history of political parties, the intersection of social movements and formal politics, and the politics of social and economic policymaking. My book, The Polarizers: Postwar Architects of Our Partisan Era (University of Chicago Press), offers an intellectual and institutional history of party polarization in the postwar United States. My writing has also appeared in The American Prospect, Boston Review, Democracy, The New York Times, Politico, and Vox.

  • The Polarizers

    Postwar Architects of Our Partisan Era

    Even in this most partisan and dysfunctional of eras, we can all agree on one thing: Washington is broken. Politicians take increasingly inflexible and extreme positions, leading to gridlock, partisan warfare, and the sense that our seats of government are nothing but cesspools of rancor, childishness, and paralysis. The shocking reality, though, is that modern polarization was a deliberate project carried out by Democratic and Republican activists.


    In The Polarizers, Sam Rosenfeld details why bipartisanship was seen as a problem in the postwar period and how polarization was cast as the solution. Republicans and Democrats feared that they were becoming too similar, and that a mushy consensus imperiled their agendas and even American democracy itself. Thus began a deliberate move to match ideology with party label—with the vexed results we now endure. Rosenfeld reveals the specific politicians, intellectuals, and operatives who worked together to heighten partisan discord, showing that our system today is a product not solely of gradual structural shifts but of deliberate actions motivated by explicit agendas. Rosenfeld makes clear that the story of Washington’s transformation is driven both by institutional change and by grassroots influences on the left and the right.


    The Polarizers brilliantly challenges and overturns our conventional narrative about partisanship, but perhaps most importantly, it points us toward a new consensus: if we deliberately created today’s dysfunctional environment, we can deliberately change it.

  • Review quotes

    Matthew Yglesias, cofounder and senior correspondent, Vox

    “Partisan and ideological polarization are defining features of our time, but they are more often denounced than understood. In The Polarizers, Rosenfeld sheds much-needed light on the origins of present-day politics—revealing the human actors who took deliberate steps to bring about the political alignment we know today. His readable, deeply informed narrative should change the way we think about the recent past and even our own times, showing the era of polarization to be not a fall from grace but a plausible response to the very real problems and dilemmas of the old political order. Rosenfeld’s new research and new insights brilliantly challenge much over-crusted conventional wisdom about polarization, and offers hints as to how conscious political action can help redress the flaws of the current party system much as past actors took steps to cure the ills of the past.”


    Andrew Hartman, author of A War for the Soul of America: A History of the Culture Wars

    “Using impressive, indeed herculean, amounts of archival work, Rosenfeld shows that as more and more Americans became politically aware and as, in the wake of the polarizing 1960s, people found ideological cohesion around economic and cultural issues, a growing number of ideologically driven and issue-based activists worked to ensure that the Democratic and Republican Parties respectively represented their cohering interests. Rosenfeld’s analysis is built upon a surprising irony: the very partisanship that so many pundits now lament was something that pundits of an earlier era wanted! The Polarizers is a provocative book that unlocks the black box of partisan polarization.”


    Julian E. Zelizer | author of The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society

    “Many observers complain about partisanship in contemporary politics, but Rosenfeld provides a careful and fascinating history of the people who created our current system. Frustrated with the way that bipartisanship had created gridlock in the 1950 and 1960s, partisan entrepreneurs such as Paul Butler believed that strong and ideologically cohesive parties would offer a better way to govern. They believed that partisanship promised to make a stronger democracy. Through tremendous archival research, Rosenfeld shows how this all happened and provides a fresh perspective on the roots of our current system.”


    Ira Katznelson, author of Fear Itself: The New Deal and the Origins of Our Time

    “Less an elegy than an illuminating genealogy, The Polarizers places today’s sharp partisanship in historical context. Moving fluidly between fascinating particulars and systematic analysis, the book’s rich account of persons, motivations, and mechanisms illuminates central transformations within American political life, all the while offering acute judgments about the party system, past and present.”


    Journal of Politics

    “A remarkable achievement ... As a political history of the post–World War II era, The Polarizers provides a comprehensive analysis of both parties’ development. The fact that Rosenfeld manages to cover both parties in this regard is impressive.”


    Perspectives on Politics

    "Academics, especially political scientists, have provided a wide range of empirical evidence of increased polarization (particularly among elites) in American politics ... but what has been missing from recent political science work has been a focus on micro-level mechanisms operating in the modern era. ... Sam Rosenfeld fills this gap by providing a detailed account of these micro-level processes. Using a vast array of archival sources, he documents how polarization is largely the result of the initiative of a few key individuals wishing to instill national ideological unity in the parties in the face of competing pressures for local constituencies."


    Kirkus Reviews

    "A delight for policy wonks and politicos, Rosenfeld's insightful study of the development of political parties since World War II is highly instructive for our current moment."


    Norman Ornstein, Democracy

    "As Sam Rosenfeld documents in his important new book, the polarization that resulted did not just happen, was not simply caused by people moving from one part of the country to another—it was presaged decades earlier, and pushed by a bevy of influential people ... Rosenfeld gets it just right, through prodigious research in the archives, including sifting through countless volumes of historical papers of the participants, and writes about it clearly and compellingly."


    Lee Drutman, Washington Monthly

    "For anyone who cares about our political future enough to learn from its past, The Polarizers is absolutely essential reading."


    Sam Tanenhaus, The New Republic

    "As Sam Rosenfeld shows in The Polarizers, the irrational-seeming “extreme partisanship” and “tribalism” that contaminate our politics today originated in the principled efforts of writers, activists, and politicians who thought the two parties needed more polarization, ideological fixity, and internal discipline."


    James Bowman, Weekly Standard

    “To some political junkies, reading Sam Rosenfeld’s book will be an exercise in almost unbearable nostalgia for that world of political stability and comity and the kind of genuine debate that can only come with mutual respect between those of differing political points of view. . .[The Polarizers] is a tribute to the meticulousness of his scholarship in reconstructing such a difficult and complicated history, one that was complicated, at least in part, deliberately.”


    Fred Siegel, City Journal

    "'When partisan team spirit becomes reinforced by shared substantive beliefs on core issues,' notes Sam Rosenfeld, 'peoples’ partisan identities become a more intensely felt component of their self-identities. Righteous passion for one’s own side intensifies while distrust of and hostility toward the other side deepen.' He’s right . . ."



    “A timely and significant contribution to the literature on political sorting and polarization that defines the current state of the two major American political parties. . . .A readable and well-structured history of our current party system. . .Highly recommended.”


    LSE Review of Books

    “A thorough and detailed study that introduces readers to the myriad figures who contributed to the development of what Rosenfeld deems the ‘polarization without responsibility’ of our present times.”

  • Publications and Media


    The Polarizers: Postwar Architects of Our Partisan Era (University of Chicago Press, 2018).


    “Party Blobs and Partisan Visions: Making Sense of Our Hollow Parties.” In The State of the Parties: The Changing Role of Contemporary American Parties 8th ed., edited by John C. Green, Daniel J. Coffey, and David B. Cohen (Lanham, MD: Rowman & Littlefield, forthcoming). With Daniel Schlozman.


    “The Hollow Parties.” In Can America Govern Itself?, edited by Frances Lee and Nolan McCarty (New York: Cambridge University Press, forthcoming). With Daniel Schlozman.


    "Prophets of Party in American Political History." The Forum 15.4 (2018): 684-709. With Daniel Schlozman.


    Fed by Reform: Congressional Politics, Partisan Change, and the Food Stamp Program, 1961-1981.” Journal of Policy History 22.4 (2010): 474-507.

    Works in progress

    “A Mix of Motives: The Georgia Delegation Challenge to the 1968 Democratic Convention and the Dynamics of Intraparty Conflict.” Working paper with Nancy Schwartz.


    “The Declinist Era in Party Scholarship: An Intellectual History.” Working paper.


    “Party Architects: Liberal Origins of Modern Party Polarization.” Working paper.


    Book project on party development from Martin Van Buren to Donald Trump. With Daniel Schlozman.

    Selected other publications

    "The Democratic Party is moving steadily leftward. So why does the left still distrust it?" Vox, June 22, 2018.


    "How Feminists Became Democrats," Politico, February 3, 2018.


    "Can Steve Bannon Realign American Politics?" New York Times, December 8, 2017.


    "Two Cheers for Polarization." Boston Review, October 25, 2017.


    "There's No Going Back," review of The Great Exception by Jefferson Cowie, Democracy: A Journal of Ideas (Spring 2016).


    "Should Liberals Back Public Employee Unions?," review of Government Against Itself by Daniel DiSalvo and Bring Back the Bureaucrats by John J. DiIulio, Jr. The American Prospect (Summer 2015). With Jake Rosenfeld.


    Smooth Operator,” review of The Whole Damn Deal by Kathryn McGarr. The American Prospect (September 2011).


    A Long-Distance Runner,” review of Citizen Rauh by Michael E. Parrish. The American Prospect (December 2010).


    Frustrated by His Own Party,” review of Roosevelt's Purge by Susan Dunn. The American Prospect (November 2010).


    The Way of the Hammer.” The American Prospect (November 2006).


    The Truth About the Senate,” review of The Most Exclusive Club by Lewis Gould. The American Prospect (December 2005).


    Disorder in the Court.” The American Prospect (July 2005).


    Recent media appearances

    PBS Digital Studios' "America From Scratch," August 25, 2018.


    The Ezra Klein Show podcast, June 30, 2018.


    Slate's The Gist podcast, May 22, 2018.


    The Atlantic with David Frum, April 8, 2018.


    The Majority Report podcast with Sam Seder, February 21, 2018.


    Thinking Aloud with Marcus Smith, BYURadio, February 9, 2018.


    New Books Network podcast, February 5, 2018.


    WAMC, January 31, 2018.


    CTV News, July 21, 2016 and November 9, 2016.


  • Teaching

    Courses taught

    Colgate University

    American Political Development - Syllabus

    War and the Shaping of American Politics - Syllabus

    American Elections and Party Power - Syllabus

    The Presidency and Executive Leadership - Syllabus


    Hamilton College

    Topics in Public Policy: College Financing - Syllabus

    Senior Project Seminar: The American Welfare State - Syllabus

    American Political Development 

    Political Parties and Elections

    The American Political Process - Syllabus


    Wesleyan University

    American Political Development

    American Government and Politics

    American Political Parties

  • Contact

    Sam Rosenfeld

    Assistant Professor, Department of Political Science

    Colgate University

    13 Oak Drive

    Hamilton, NY 13346




    cell: 202-487-9103

    work: 315-228-6464