How Far Can Germany's Social Democrats Bend Before They Break?

BERLIN—For Germany’s beleaguered Social Democrats (SPD), party unity seems to be in short supply these days. Following a turbulent, six-hour special conference at Bonn’s World Conference Center on Sunday to decide whether the SPD should enter a coalition with Chancellor Angela Merkel, delegates of the center-left party stood together to sing “When We Stride Side by Side,” their traditional hymn. Appearances aside, however, this was no kumbaya moment.

Earlier that day, Martin Schulz, head of the SPD, had taken the stage to appeal to the more than 600 delegates in attendance to back an agreement he and his fellow party leaders had hashed out with Merkel’s conservative bloc, which is composed of the Christian Democrats (CDU) and Christian Social Union (CSU). Schulz assured his delegates that governing alongside Merkel gave them a chance to halt the wave of right-wing populism sweeping across Europe. Working with