The rising tension at a large St. Paul charter school mirrors the clashes nationally between school leaders and charter school teachers who try to unionize.

Teachers at Community School of Excellence say school leaders' plan to fire 20 teachers, most of them union members, was a union-busting move. School leaders disagree, but reinstated some of the fired teachers this week.

From California to New York City, similar complaints have surfaced as teachers push for voices in school decisions and sometimes face fierce opposition from the school operators.

California lawmakers are auditing Los Angeles' largest charter organization to see if anti-union acts were conducted using public funds. Earlier this year, a Chicago charter network had to hire back teachers it fired after workers voted to unionize. This week, a Cleveland charter school reached a contract after the charter network was accused of unfair labor dealings.

Minnesota's charter schools are publicly funded and exempt from some regulations and union requirements, but teachers here and elsewhere have unionized and fought for employment protections and salary increases.

Though many charters have been resistant to unions, teachers' unions lately have made inroads in cities like Cleveland, said Todd Ziebarth, senior vice president at the National Alliance for Public Charter Schools.

While teachers desire a say in school operations, some administrators don't want to lose their flexibility in staffing, Ziebarth said.

He estimated the number of unionized charters has remained constant at anywhere from 10 percent to 15 percent. In Minnesota, two charters have unions; another three have been in talks with statewide teachers' union Education Minnesota in the past month or so, the organization said.

Charters here and nationally

Charter schools were born in Minnesota in the 1990s as public schools with a mission to provide a space for teacher experimentation. All traditional school districts in Minnesota have local teachers' unions affiliated with Education Minnesota.

Charter school salaries vary, said Eugene Piccolo, executive director of the Minnesota Association of Charter Schools. A teacher with a master's degree and five years' experience can make about $45,000 at Community School of Excellence compared with $49,000 at a traditional St. Paul school, for example.

Nationally, the American Federation of Teachers is reporting an increase in unionized charters, in part because people now view charter schools as a career rather than a temporary stop, said President Randi Weingarten. She also sees an increase in fights between teachers' unions and administrators, she said.

Jeanne Allen, CEO and founder of Washington, D.C.-based Center for Education Reform, counters that she has seen a decrease in unionized charters.

Minnesota isn't seeing a trend toward union charters, Piccolo said.

"It has struck me in the cases where this has occurred, you have to look at what's been going on in the school and people feeling like they have no other way of impacting things," he said.

Organizing in a charter school can pose difficulties, said Denise Specht, president of Education Minnesota. Educators can lose their jobs quickly for pointing out issues, and the frequent turnover means there isn't "a constant staff roster that believe in moving toward a collective voice," she said.

The St. Paul situation

At Minnesota's other union charter school, the Twin Cities German Immersion School in St. Paul, teachers didn't face major pushback when negotiating for due process and a salary increase, said union president Scot Stephenson.

It's different at Community School of Excellence, a Hmong culture school with about 1,000 students. Teachers formed the union in 2014 and have been negotiating for their first contract for a year, said Rob Aurand, a teacher and the school's union treasurer. The administration had been hostile, said Blythe Inners, president of the school's union. Last week's firings included four of the five members of the school's negotiating team and the president. Seven of the fired teachers were told they had jobs Tuesday, including Aurand, he said.

Contract negotiations are continuing, though the school's status is in jeopardy. The school is losing its authorizer and is in talks with a potential replacement, Minnesota Guild. Without an authorizer, the school will close July 1.

Bao Vang, the school's chief executive, said she is optimistic that the school will stay open and there's been great progress on negotiations.

"We have worked really hard to change the culture here," she said.

Aurand said the union's priority is bargaining for job protections.

"This process has certainly shaken my faith in this administration," he said.

Beena Raghavendran • 612-673-4569