Republicans are watching the split within labor with relish, foreseeing a weakened political adversary. But labor experts were divided over the potential consequences of a fractured labor movement. Some suggested that internal competition could help to stop the steady decline in union membership, and all of those interviewed said defections from the AFL-CIO would not necessarily harm organized labor.

AFL-CIO President John Sweeney sharply criticized the actions of the five labor leaders. "Now more than ever we need a united labor movement," he said. "The clearest path to growing the union movement and helping more workers form unions is by exercising our greatest strength — solidarity."

The five dissident unions — the Service Employees International Union, the Teamsters, Unite Here, the Food and Commercial Workers and the Laborers — have tried to persuade the central labor federation to shift resources into organizing and to strengthen the authority of the AFL-CIO over its 58 member unions.

Moreover, these unions have sought to defeat Sweeney, who is up for re-election in July.

The dissident unions have repeatedly been thwarted in their efforts because they represent only 35 percent of the AFL-CIO membership and have been unable to win over other supporters. Sweeney is now virtually assured of re-election and he has more than enough votes to defeat the dissidents' proposals when the AFL-CIO meets in Chicago at the end of July.

The dissidents' inability to win on any front has served to increase the chances that some or all will quit the labor federation. The leadership of the SEIU, Unite Here and the Food and Commercial Workers have already begun the process to "disaffiliate," and Teamsters are likely to do so at the next executive committee meeting.

The five union leaders said they have not yet agreed on staffing, a budget or officers for the "Change To Win Coalition" which will have the goal of organizing "the tens of millions of workers in the private sector who are desperate for a voice on the job."

In a joint statement, the unions compared formation of the coalition to the creation in the 1930s of the Committees for Industrial Organization, which broke away from the American Federation of Labor to organize entire industries like steel and auto.

Harvard professor Richard Freeman and Elaine Bernard, director of Harvard's labor and work life program, separately said conflict within labor could be productive.

"Competition is very good for unions as well as for everyone else, and the last time unions grew was after the CIO split from AFL," Freeman said.

"You can date the decline in union density from the time AFL and CIO became one (in 1955). ... The politics that led to this division is largely positive, but the new gang may not have much of a better strategy than the old gang."

Bernard pointed out that in Canada, the highest union density is in Quebec, where there are three competing labor federations.

Two other experts, Kent Wong, director of the Labor Center at the University of California Los Angeles, and Richard Hurd, labor studies professor at Cornell, said the 1930s, when the political environment organizing, is not comparable to today.