While union membership flatlined nationally over the past year, something surprising happened in the Lonestar State. Texas had its biggest surge in union membership density in the past decade.

The growth comes as the result of booming economic growth and shifting political demographics. Texas’ political leaning is becoming increasingly polarized between deeply right-wing rural areas and progressive cities, where elected officials have helped labor organizers put down roots. Even in rural parts of the state that tend to vote against business regulation locally, private sector unions have been able to attract members with apprenticeship programs that guarantee higher wages.

According to the Bureau of Labor and Statistics (BLS), Texas union membership grew by 80,579 in 2017. Density increased 0.63%, which is the biggest jump since 1993, the year that “right to work” laws were enacted in the state. Another surprise: nearly two-thirds of that growth was in the private sector.

Private construction unions are one group that is eager to point to its progress over the past year as a sign of more growth to come. Private construction made up about 18 percent of the growth in new union membership. While this group had huge gains over the past year, it’s only expected to grow more in response to the post-Hurricane Harvey response effort.

That activity will spike over the next year once the Federal Emergency Management Agency funding starts pouring into the gulf according to Paul Puente, executive secretary of the Houston Gulf Coast Building and Construction Trades Council. While the unions generally stick to commercial and industrial sector, many houses will need work on their foundations that requires steel and cement work by more specialized union labor.

“We’re scouring the community for individuals who were directly affected by Harvey and we provide them with training and education at no cost to them,” Puente said about the apprenticeship programs the trade council has set up.

The union uses advertising to reach a wide network of Texans throughout the gulf looking access to higher wage jobs. Full participation in apprenticeship readiness program ensures a weekly stipend of $250 and zero debt to receive training in technical skills like plumbing, electrical work and ironwork. “It’s hard to look away and say I don’t want to be a part of a union when the union is actually providing you with all those benefits,” said Puente.

Puente attributes the growth over the past year to the changing perception of construction unions as business-friendly. “We have a no-strike agreement,” he said. “We pride ourselves to be able to be as flexible as we can to our customer and our clients’ needs. That messaging has helped us gained market share.”

Puente sees marketing strategies, like the advertising spot the trades council buys on University of Houston sports broadcasts as softening the image of labor unions in the eyes of the white collar workers. “We’re business people. We want to represent the workforce and the industry and good work ethic,” Puente said.

An increased amount of white collar cooperation has helped private sector unions grow said Ed Sills, communications director of the Texas American Federation of Labor and Congress of Industrial Organizations. “A lot of people are under the misimpression that labor doesn’t want corporations to do well. We do, when we get a share of it,” he said.

Teachers’ unions have also been making small but steady gains in the past several years said Sills. Though the membership of the teachers unions is still in recovery from 2011 when the state senate passed a $5.4-billion cut to public schools, resulting in thousands of teacher layoffs. “That really set things back,” said Rob D’Amico, communications director for the Texas American Federation of Teachers (AFT).

In the years since then, the Texas AFT has focused its efforts on grassroots organizing. “The best issues to organize around are always local issues,” D’Amico said. Among these, unpopular principals are an evergreen issue. Ross Moore, president of the El Paso AFT, relied on this approach to revitalize a chapter that had been stagnating. Moore focused on everyday “nuts-and-bolts issues”–personal leave, class sizes, improperly introduced new curriculum–to build his membership.

Since AFT can’t participate in collective bargaining under the restrictions of the state’s “right to work laws,” they use elective consultation, an approach that necessitates the union’s aggressive involvement local politics. In this method of bargaining, the local union works to elect school board members who facilitate budget negotiations in its interest.

This type of venture into the political realm is not unique to the public sector in Texas. UNITE HERE Local 23, a national union representing food service, airport and hotel industries has used a progressive platform to draw attention to the disparity between falling unemployment and stagnating wage growth. The union has offices in Austin, Dallas, Houston and San Antonio. “What we try to get our membership to see is that the union rights are civil rights and civil rights are unions rights. We’re trying to expand the scope of union activity to social justice issues,” said William Gonzalez, president of the Texas chapter.

In the past year, the union organized the Marriott Marquis Houston, a 1,000-room hotel that opened at the end of 2016. Gonzalez says that the state’s membership is most concentrated in Houston, where membership has reached 3,000. He expects it to grow by over 1,000 in the next year. Gonzalez sees part of the bump in the Texas branch’s numbers as a reaction to perceived anti-immigration sentiments of President Trump and Gov. Greg Abbott. He thinks that politics is integral to the state’s union growth.

UNITE HERE’s approach to organizing involves both national and local campaigns, taking some of the focus off local politics. “In our industry, they’re all multinational corporations. If you don’t have some national component to it, then they can just compound their resources into that one location,” Gonzalez said.

Regardless of political posture, the union leaders agree that pro-union sentiments not only carry across sectors, but state lines. Sills says that the membership gains in Texas are part of a larger trend of union growth in southern “right to work” states. “You can go to almost any state, you can find substantial organizing activity. There’s more of a culture of organizing than ever before, and I’ve been in this job about 24 years,” said Sills.

“When other unions win, we win,” Gonzalez said.