By Ricardo Lopez and Beena Raghavendran

Minneapolis Star Tribune

The U.S. Supreme Court began deliberating a case Monday that could dramatically curb the financial and political power of public-sector unions in Minnesota and more than 20 states around the country.

“It is hugely significant,” said David Larson, a professor of labor and employment law at the Mitchell Hamline School of Law. “It has to do with the viability of labor unions and their ability to finance themselves.”

A group of local union workers gathered Monday at Minnesota AFL-CIO headquarters to track the oral arguments on social media and discuss the possible implications on their own lives.

The case will decide whether unions have the power to require nonmembers to pay union dues. Under current law, a union is allowed to collect dues from all workers — not just members — when they negotiate wages, benefits and other workplace conditions.

A favorable ruling for the plaintiffs could cost unions millions of dollars in dues, money that labor groups have relied on to help mostly Democratic candidates and causes. Republicans have tried for decades to erode union influence in politics, and also to limit their negotiating power with businesses and governments.

“If unions lose resources, workers lose power,” said Jennifer Munt, spokeswoman for AFSCME Minnesota Council 5. “It’s really that simple.”

Supreme Court justices on Monday seemed critical of the idea that unions should have a guaranteed right to impose dues on nonmembers, leaving open the possibility that the practice would come to an end.

The plaintiffs, 10 California teachers, argue that even basic union tenets — such as contract negotiations — should be considered political activity because public-sector unions are negotiating with the government over pay, benefits and other workplace issues. Moreover, they argued that some positions by teachers unions, including support for layoffs and school assignments based on seniority, were at odds with their own views, making them effectively paying for the unions to argue against their own best interests.

A decision could have a huge impact in Minnesota, a state with a relatively strong labor movement that has played a role in nearly every corner of state and local politics. Minnesota is among 19 states that have higher union representation than the national rate of 11.1 percent, according to a 2014 report by the U.S. Bureau of Labor Statistics. In Minnesota, 360,000 workers are members of unions, for a rate of 14.2 percent. Counting nonmembers whose jobs are covered by unions, that number rises to 380,000, according to the 2014 report.

Minnesota law stipulates that employees who don’t elect to be in unions pay no more than 85 percent of the dues that unions charge full members.

Minnesota labor groups have held at least two events in recent weeks trying to highlight what they say is the positive role of union workers in the state. Union leaders said the court case represents broader attempts to reduce the power of public-sector unions, which ultimately will harm workers.

Education Minnesota, the statewide union representing 70,000 educators, collected nearly $28 million in union dues, according to 2014 tax records. AFSCME Local 5, which represents many state, county and municipal government employees, collected $21 million in dues that year.

Labor unions have used the money to fight for their workers and have become a powerful political force in the state.