With the nation gearing up for the 2016 presidential election, it’s an ideal time to look at a recently published book by Daniel Schlozman, assistant professor in the Department of Political Science. His book, When Movements Anchor Parties: Electoral Alignments in American History, explores the ways social movements have played critical and crucial roles in American politics since the Civil War.

In particular, the book, an outgrowth of Schlozman’s graduate school dissertation and published by Princeton University Press, examines how two movements—organized labor and the Christian Right—have become deeply embedded in the two-party system and exhibited an ability to survive and be effective to this day.

Meanwhile, other movements, such as the abolitionists after the Civil War, the populists of the 1890s, and the anti-war activists of the 1960s, failed to carve lasting niches in the system for a host of reasons.

Part of a movement’s ability to succeed and endure comes from its capacity to deliver blocs of voters and resources for a sustained amount of time, Schlozman says. But political and organizational prowess among movement leadership is vital as well.

“You have to be very politically shrewd to keep a movement organized,” Schlozman says, “especially with all of your radical cadres that think things that are unacceptable to mainstream voters, and at the same [you have] to keep ordinary voters involved and have some sense of what some attainable policies are going to be. It requires a lot of political strategy.”

Schlozman says movements historically tend to decline when they lose vision, splinter, offend powerful party factions, or fail to be politically pragmatic.

For instance, Reconstruction faded from the landscape when the Republican Party realized that empowering African-Americans could hurt Northern industries and benefit trade unions, he says.

Also, Schlozman says, the anti-war movement of the late 1960s and early 1970s split apart before the nomination of Senator George McGovern in the 1972 presidential race, largely due to growing factionalism and a loss of organizational focus.

“These are very complicated multilevel games,” Schlozman says. “The people who succeed learn how to play them right.”

What an anchor movement provides is firmness and stability for parties while offering opportunities for coalitions and policy development, he says. Often, they help provoke change in a party’s direction, largely because of the passion brought to the fore by a movement’s rank and file.

“All of the succeeding movements have, in one sense or another, that same creedal passion, and that’s what makes them interesting and challenging to the party system,” says Schlozman.

While organized labor and the Christian Right have experienced peaks and valleys during their histories, they have shrewdly maintained anchor roles in the political system, he says. But such recent movements as the Tea Party and Occupy have not demonstrated the same stamina and infrastructure required to endure. He says the jury is still out on whether Black Lives Matter will prove to be an effective social movement with the infrastructure and political means to thrive and endure.

While their core values differ, the common ground between organized labor and the Christian Right are their structural positions within the parties and their ability to inspire ordinary people, Schlozman says. Their activists, he says, tend to be individuals motivated by altruism rather than material or personal gain.

“These movements express fundamental views of the American experiment about liberty and equality and what freedom means, and of the civic responsibilities we have to one another,” he says. “When you have different views about this important stuff, you have disagreements. We should have a political system that has those disagreements and allows us to work them out.”

Although the information age has enabled movements to mobilize troops rapidly, Schlozman believes the old-fashioned mechanisms for networking and formulating policy will prevail.

“My hunch is face-to-face organization is still important, and people dedicated to a movement will still want to do that with people they know in their neighborhoods rather than just by typing hashtags,” he says.