United Steelworkers spokeswoman Jess Kamm Broomell said the union is "disappointed with the court's decision and even more concerned that Duquesne's administration would fight this hard to keep their workers from having a voice on the job."
"Unlike other Catholic universities that recognized adjunct faculty unions, the Duquesne administration decided to invoke its status as a religiously affiliated institution in an effort to stop adjuncts from joining together to improve their working conditions and the university community," Kamm Broomell said.
It is unknown whether the national labor board will appeal the ruling, the Pittsburgh Post-Gazette reports.
Catholicism in America has had a long tradition of supporting labor unions. The U.S. Conference of Catholic Bishops issues a statement every Labor Day. The U.S. bishops were critical of a major 2018 Supreme Court ruling striking down mandatory fees paid to public-sector unions, which they said undermines workers. They cited Benedict XVI's 2009 encyclical Caritas in veritate, which defends labor unions and objects to limits on their freedom.
In her dissent from the appellate court ruling, Judge Cornelia Pillard argued that the ban on unionization under national labor board rules applies only to full-time faculty, not part-time adjuncts who "often have a very different role."
"It is not at all apparent that temporary, part-time adjuncts whom the school does not even hold out as agents of its religious mission necessarily fall within an exemption from the National Labor Relations Act that was drawn to account for the 'critical and unique role' of faculty in 'fulfilling the mission of a church-operated school'," she said.
Welsch said that in the wake of the court decision, Duquesne president Ken Gormley is "committed to taking a fresh look" at the university's engagement with adjunct faculty.
"The university looks forward to working with our adjuncts, and indeed with all of our faculty and staff, to identify the right solutions for our wonderful community of scholars, teachers, and learners in the context of our unique mission," Welsh said. "Our Catholic and Spiritan mission requires nothing less."
The court also recognized the Catholic identity of the school.
"Duquesne holds itself out as providing a religious educational environment by publicly identifying itself as a Catholic institution guided by Catholic principles, providing regular Catholic religious services on campus, and encouraging students to participate in religious study groups, lectures, and projects," the appellate court's ruling said.
The court cited the danger of labor board intervention if a school took action against teachers for failing to comply with religious principles and of entanglement in questions like judging the content or application of religious principles.
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The lack of jurisdiction similarly means the labor board "will not get involved in disputes between churches and their employees for fear of interfering with the churches' religious missions."
The court faulted the labor board's framing of the issue, saying it pitted academic freedom against religious mission, both because this view entangled the board in adjudicating religious claims, and because it excluded the possibility that the faculty's exercise of academic freedom might be understood as serving a religious mission.
The Association of Catholic Colleges and Universities, which filed an amicus brief in support of Duquesne, said the case was about how the government decides to recognize faith-based institutions. The labor board, in the association's view, "chose to limit the designation of 'Catholic' strictly to the work that is done by professors teaching religion or other narrow corners of our institutions to be decided, institution-by-institution, by the NLRB itself."
"No government office should ever have the power to decide, department-by-department, course-by-course, which ones are doing the Church's work and which ones are not," the association said.
Court precedents articulate "the problems that can arise when a government office decides what activity is religious and what is not." While acknowledging that a number of its Catholic campuses welcome labor unions, the association said that "empowering government offices to decide which components of a university are faith-based is simply the wrong way to protect faculty."
The appellate court ruling said that because the court has established that the labor board does not have jurisdiction over religious schools and faculty, it did not need to address the plaintiff's claims that the board lacks jurisdiction for other reasons and claims that the board violated the Religious Freedom Restoration Act.