D.N.C. Staff to Join Union, in a Milestone for Labor

Staff members at the Democratic National Committee are set to be represented by a union, the first time a national party organization will have a unionized work force, committee officials said on Tuesday.

Roughly 150 employees at the committee will join the Service Employees International Union Local 500, a group that represents public-sector workers in the District of Columbia and across Maryland. They agreed to unionize through what is known as a card-check system: A majority of eligible staff members at the D.N.C. signed cards opting to form a union....