After a failed revolution in 1848, hundreds of Germans were expelled from their home country and settled in the US. It was not obvious that this eclectic group would play an important role in American politics and change the course of the nation.

Their words and leadership helped President Lincoln and the North win the Civil War, according to a paper in the American Economic Review.

Authors Christian Dippel and Stephan Heblich found that these German immigrants significantly boosted Union Army enlistments through newspapers, social clubs, and public speaking tours.

The story of these so-called Forty-Eighters offers important insights into how grassroots leaders shape social movements.

Dippel recently spoke with the AEA's Tyler Smith about getting around something economists call the "reflection problem," the legacy of the Forty-Eighters, and what their example offers today's leaders.