From there, they built a platonic relationship that lasted for a few years. They privately knew that some romantic feelings remained, but they ignored them for the sake of preserving the friendship. They didn’t speak much about their past romance.
A turning point came in 2017. On the day of the presidential inauguration of Donald J. Trump, Ms. Stackl and Mr. Campbell each took part in protests around the National Mall. They attended separately. At one point, though, they spotted each other across a sea of people. The pair locked eyes for a few moments — it was a steady and supportive gaze in an otherwise deeply uncertain situation.
“I remember he gave me this gentle, affirming smile,” Ms. Stackl said.
They started communicating more and more after that day. By the end of that summer, they were back together. Soon after, Mr. Campbell left for a yearlong study period in Buenos Aires, during which time the couple traveled around South America together. Ms. Stackl introduced Mr. Campbell to her extended family in Chile. When Mr. Campbell returned from his studies, the couple moved in together.
Mr. Campbell proposed in the fall of 2019.
Ms. Stackl, 35, a senior communications specialist for Greenpeace USA, and Mr. Campbell, 33, a policy adviser for Representative Jesús G. García, Democrat of Illinois, were married March 20 in the bride’s mother’s backyard in Silver Spring, Md. The ceremony was led by Kathleen Brower, a friend of the couple who is a nondenominational minister.
Ms. Stackl and Mr. Campbell pointed out that their work in environmental and labor activism — both generations-long issues that call for day-to-day struggles in service of a long-term goal — have, in an indirect way, prepared them well for marriage.
“We know, realistically, that a relationship is not always going to be easy,” Ms. Stackl said. “There are going to be hard days, there are going to be hard months, even. But we are willing to fight for the relationship — for each other.”