In this March 12, 2015, Don Brown of Hudson, a Fairpoint employee and member of the Communications Workers of America, speaks as dozens of labor activists meet at the State House in Augusta. Credit: Mario Moretto / BDN

Lawmakers on Monday debated whether Maine should become the next right-to-work state, the latest in the battle over legislation that Democrats and union activists say would weaken organized labor.

But unions in the Pine Tree State, like elsewhere in the nation, have already long been on the decline. Currently, 11 percent of Maine workers are members of a union, just slightly below the national average of 11.1 percent.

Union membership in Maine has traditionally been below the national average, though Maine union membership briefly surpassed national membership in 2000, when 13.8 percent of Maine workers belonged to a union compared with 13.3 percent for the nation, and in 2012 when 11.5 percent of Maine workers belonged to a union compared with 11.3 percent nationally.

According to a 2004 Congressional Research Service report, union membership in the U.S. peaked in 1954 at 34.8 percent of the workforce. During the 1970s and 1980s, unions saw sharp declines in membership, from 27.4 percent in 1970 to 15.9 percent in 1989.

The decline in union membership and unions’ influence has happened over a time of economic transition as traditionally union-heavy industries such as manufacturing have given way to the service sector and tech startups whose workers are much less likely to unionize.

A changing economy has eroded union ranks. According to Marc Cryer, director of the Bureau of Labor Education at the University of Maine in Orono, the loss of manufacturing jobs has contributed to declining union membership in a big way. Maine has seen a number of manufacturing industries decline, among them pulp and paper, shoes and textiles.

In 1960, one in three jobs in Maine were in manufacturing; today that figure is one in 12.

Union representation has been more common in manufacturing than any other part of the private sector. In 1994, 17.5 percent of workers employed in manufacturing belonged to a union, but by 2014 that number fell to 9.7 percent. Today, union membership in manufacturing trails construction (13.9 percent), telecommunications (14.8 percent), transportation (19.6 percent) and utilities (22.3 percent).

But some recent attempts to expand union ranks within manufacturing, like the United Auto Workers’ move in 2014 to unionize a Volkswagen plant in Tennessee, have been unsuccessful.

While manufacturing jobs have disappeared, service-oriented industries such as retail and tourism have grown, which are industries that typically aren’t easy to unionize, Cryer said. The U.S. Bureau of Labor Statistics reports that 4.2 percent of retail workers are unionized, and 3.2 percent of people employed in leisure and hospitality belonged to a union.

Unions today face similar odds across the private sector. In 1994, 9.2 percent of workers in the private sector were unionized. Twenty years later, union membership in the private sector fell to 6.6 percent.

Unions, however, maintain a strong presence in the public sector. According to the Bureau of Labor Statistics, 35.7 percent of public-sector workers are in a union, which is down from 37.7 percent in 1994. A majority of unionized workers in the public sector are at the municipal level.

An aging workforce also presents a problem for unions. Baby boomers have the highest rate of union membership of any age group. According to the Bureau of Labor Statistics, 27.9 percent of workers age 45 to 64 were union members in 2014. As boomers continue to retire, union ranks will continue to decline.

Attracting younger workers will be key for unions to offset the loss of the baby boomers. But union membership has not shown any growth among millennials. Of workers age 16 to 34, only 14 percent were in union ranks in 2014, down from 17.6 percent in 1994.

This, Cryer said, “doesn’t bode well [for unions]. Unions are going to have to bridge that gap somehow.”

Low union membership among millennials is a reflection of an economy that has grown in areas that aren’t dominated by unions. Millennials first entered the workforce during the height of the Great Recession, which precipitated a decline in manufacturing work and led to cutbacks in the public sector.

Even though they aren’t finding their way into union jobs, millennials, more so than any other age group, have a positive view of unions. According to the Pew Research Center, 55 percent of 18- to 29-year-olds approved of unions, compared with 29 percent who did not. Older Americans are more divided in their views on unions — 46 percent of 50- to 64-year-olds approved of unions compared to 43 percent who did not.

To reverse decades of decline, unions will have to look to new sectors. A national movement has begun to unionize fast food workers, which has been part of a larger push to increase the minimum wage. Since November 2012, fast food workers at franchises across the nation have led seven walk-outs. These workers, who are largely not union members (only 1.4 percent of food service workers belong to a union), received financial support from the Service Employees International union.

Cryer said that if unions want to increase their ranks, they will have to “go out and organize people they usually don’t organize.”

Some local unions are doing just that. Last week, pharmacists at 16 Shaw’s Supermarket stores approved a move to join the Teamsters Union Local 340, adding 21 to its ranks. And only two years earlier, the International Association of Machinists and Aerospace Workers succeed in organizing Maine lobstermen, adding nearly 600 to that union’s ranks.

What does all this mean for unions? Without a high density of membership, unions are losing their “financial muscle” to organize workers and engage in bargaining, Cryer said.

Opponents of right-to-work legislation are concerned that such bills would further weaken unions by allowing unenrolled workers, who currently receive benefit from union-negotiated contracts, the option to not pay representation fees, sometimes referred to as a “fair share fee.”

Cryer said that allowing unenrolled workers who receive union representation to not pay a fair share fee would hurt unions’ bottom lines, as union activities such as negotiations, lobbying, investigating worker claims of mistreatment and strikes cost money, and undercut their ability to engage in meaningful representation.