Workers are forming unions at nonprofits and think tanks. Their bosses aren't always happy.

The idea to unionize took shape last summer. And it didn't happen at a big company, school or hospital, but a more unexpected place: a small nonprofit organization.

Employees at an Austin, Texas-based think tank, the Center for Public Policy Priorities, started meeting after work to figure out how they could improve their workplace. Some workers felt there was an incongruity between the think tank's advocacy on issues such as health care, living wages and public benefits, and the way it treated its employees, according to Amanda Posson, one of the union organizers.

On Tuesday, workers at the Center for Public Policy Priorities formally opted to join a union, voting unanimously to be represented by the Nonprofit Professional Employees Union.

While generally union participation has been declining, union efforts at nonprofit entities are a bright spot for the labor movement and are the latest sign of growing momentum. Nonprofit workers, centered in Washington D.C. but also in states such as California, Maryland, Alabama, and New York, have helped swell the NPEU's ranks 30 percent over the past year. The staffs of five nonprofits opted to join the NPEU in 2019, bringing the total number of groups it represents to 19 nonprofits, or 350 members.

The numbers are just a decimal point of the 14.6 million workers who are union members nationwide. The federal government does not track union representation among the more than 12 million nonprofit workers.

But union members and labor advocates point to larger symbolism, saying the nonprofit success is emblematic of the labor movement's appeal to younger and highly educated workers nationwide, similar to the unions that have formed at digital media companies.

"Younger people are coming in, and they want more work-life balance," said Janice Fine, the research director at the Center for Innovation in Worker Organization at Rutgers University. "And they see unions as a really important tool for achieving that."

Nonprofit workplaces that have joined the NPEU this past year include the Action Network, Food & Water Watch, Jews United for Justice, Jobs to Move America, and the Washington Center for Equitable Growth.

"People think that nonprofit workers don't need unions - that we don't fit into the mold," said Kayla Blado, the president of the all-volunteer NPEU and a staffer at the Economic Policy Institute. "But millennials graduated with high levels of student debt and medical bills, which has helped open people's eyes that we're not going to get a 'middle-class' lifestyle unless we work for it."

Nonprofit organizations would seem like fertile ground for workers hoping to organize. Magnets for younger, highly educated and idealistic workers, nonprofit groups have long been known for a culture of unpaid hours, low salaries and thin budgets. And many of these think tank workplaces embrace economic policies at the heart of their public missions. Yet these practices haven't always been applied internally.

The Center on Budget and Policy Priorities, which is unrelated to the Texas nonprofit, has advocated for national paid family leave but was offering employees just two full weeks of paid parental leave, in addition to six weeks of short-term disability benefits, before the union got involved.

After about 90 workers at the organization unionized in 2018, they were able to win a contract from the company that included a wage floor of $50,000, 12 weeks of paid family leave and guaranteed cost of living raises for most of its workers for the next three years.

"CBPP is committed to making the organization the best it can be," the nonprofit group's president, Robert Greenstein, said in a statement. "I think that commitment was clear on both sides throughout the contract negotiation process, which was marked by a spirit of cooperation and an emphasis on shared values, and produced a strong result."

"Both sides got some of what they wanted and both sides got a little disappointed and ultimately everybody was happy with where we landed," said Aoife Toomey, 41, a fundraising manager and member of the bargaining committee at the CBPP's union.

Nonprofit organizations, despite their liberal bona fides, have not been known to be especially welcoming to unions.

Blado said that two of NPEU's five successful union campaigns in 2019 were particularly contentious, even at places known for their civil rights advocacy.

In November, the union filed an unfair-labor complaint against an advocacy group for transgender rights, the National Center for Transgender Equality. The NPEU said the nonprofit organization fired all of the employees in the union's bargaining unit in retaliation for their organizing work. The union pointed out the group's own research about the discrimination that transgender people face in workplaces.

The National Center for Transgender Equality dismissed the labor complaint, calling the allegations made by the union false.

"We are confident that they will be dismissed by the National Labor Relations Board after a thorough investigation," Mara Keisling, the executive director of the National Center for Transgender Equality, said in a statement. "NCTE supports the right of employees to organize, and we look forward to one day being able to proudly call ourselves a union shop."

Most nonprofit groups that unionize don't face the same level of aggressive anti-union campaigns that private-sector companies often undertake to fight workplace organizing. That's been the case for the Center for Public Policy Priorities in Texas.

"We have been very collaborative with management," said Posson, the union organizer at the Center for Public Policy Priorities. "It feels like vision aligns."

The center's chief executive, Ann Beeson, released a statement about the staff's union campaign saying that she was "excited" for her staff in the venture.