Case Study: PTB-PVDA achieves 35-seat gain in Belgian parliament with NationBuilder

How party on the rise PTB-PVDA gained 35 seats in Belgian parliament

PTB-PVDA (the Workers’ Party of Belgium) faced the challenge of scaling grassroots organizing and getting out the vote without mainstream media support. To unite dozens of local teams and build a sophisticated digital infrastructure, the party adopted NationBuilder to create forty local “nations” and a centralized, filterable database for volunteer coordination.

NationBuilder’s tools — including tag sharing, easy list segmentation, and integration with phone-banking workflows — enabled highly targeted outreach and coordinated volunteer phone campaigns. With NationBuilder powering their operation and synchronizing lists to CallHub callers, PTB-PVDA mobilized roughly 5,000 volunteers, nearly doubled its vote share to about 9%, gained 35 seats, and now holds 12 Members of Parliament and 43 elected representatives, becoming Belgium’s fifth-largest party.

PTB-PVDA