A campaign to organize adjunct faculty has run aground at the University of St. Thomas in St. Paul, where independent instructors voted against forming a union.

After a hotly contested union election, the vote was 84 in favor and 136 opposed, according to union officials.

The results, announced late Monday, dealt a setback to organizers of Adjunct Action, an offshoot of the Service Employees International Union, who had hoped to build momentum for a statewide effort to improve pay and benefits for part-time instructors.

But it was a relief for officials at St. Thomas, one of Minnesota’s largest private universities, which had lobbied intensely against the union vote.

Concerns about low pay and a lack of job security have fueled college unionizing efforts across the country, where adjuncts — mainly part-time, temporary hires — are said to outnumber permanent faculty members.

In June, adjuncts at Hamline University in St. Paul voted to create the first such union in Minnesota. But a similar election at Macalester College was called off abruptly in June amid growing dissent about the vote.

St. Thomas has more than 600 adjunct instructors in addition to 466 full-time or tenure-track professors, according to the university. In this case, the union vote was limited about 300 adjunct instructors who teach undergraduate students.

Increasingly, critics have complained that adjuncts have become the working poor of higher education, with lower pay and few of the perks of regular faculty members.

But in Minnesota, the union organizing effort has proved divisive as well. In recent weeks, a number of St. Thomas adjuncts publicly urged union organizers to cancel or delay the vote to give administrators more time to address their concerns.

Kim Sovell, who teaches marketing at St. Thomas, said she was not anti-union, “but I’m anti being ramrodded … or rushed into making a decision,” she said. She added that she was concerned that she could lose her teaching job if the vote passed. “My fears are that the business school could stop using adjuncts,” she said.

A spokesman noted that adjuncts are paid a median of $4,300 per class at St. Thomas — about $1,600 more than the national average — and that the university already has taken steps to improve wages and offer some fringe benefits.

In the weeks leading up to the vote, President Julie Sullivan held half a dozen campus meetings, appealing to adjuncts to reject the unionizing effort. In a campus e-mail, she described union contracts as “rigid and inflexible” and said it was better to solve problems collaboratively. She also said it was not a matter of money, but about preserving St. Thomas’ “unique mission” as a Catholic institution and retaining flexibility.

Sullivan, who just marked her first anniversary as president of St. Thomas, issued a statement Monday saying that she was pleased with the results, and that she looks forward to working with adjunct faculty “to find solutions” to their concerns. She said she plans to “initiate an action plan” to address the issues that have come to light in recent discussions.

“I also appreciate the trust so many of you have placed in me and our new administration,” she wrote.

On Monday, union organizers issued a statement saying: “We are disappointed with the results of today’s election, but are incredibly proud of the gains this campaign achieved by bringing the reality faced by adjuncts at St. Thomas out of the shadows. By starting this process, we’ve initiated a long overdue dialogue with leadership at St. Thomas that has not happened for far too long.”

In all, adjuncts teach about a fourth of the undergraduate classes at St. Thomas, according to the university. Many adjuncts choose to teach as a second or retirement job, not as their primary income.

In June, union organizers at Macalester decided to call off their election at the last minute after some adjuncts complained that the vote was being rushed.

But at St. Thomas, members of the organizing committee — who filed a union petition in May — said they saw no reason to delay the vote.

In the past year, adjuncts have unionized at nearly a dozen universities, including Georgetown in Washington D.C., and Tufts and Northeastern in Massachusetts, according to Adjunct Action. Only one unionizing effort was voted down — at Bentley University in Massachusetts.