NEW YORK -- Some names mentioned during the past week's transit strike might have seemed out of place in the context of contract negotiations: Rosa Parks. Martin Luther King Jr. Eugene "Bull" Connor.

The Transport Workers Union and its supporters linked their labor woes to the civil rights struggle, an approach that people who study the labor movement say is being used more often as some unions see increasing minority membership. More than 70 percent of the TWU's 33,000 members are people of color, including its president.

"In organizing itself I see a tremendous increase in the reinventing of the labor movement as the heir of the civil rights movement," said Gary Chaison, professor of labor relations at Clark University in Worcester, Mass. "I think it's the recasting of the labor movement in a way that I haven't seen in many years."

"Unions have got to find a language that justifies the actions that they are taking, they're going to have to use the language of civil rights," said Robert Korstad, associate professor of public policy studies and history at Duke University. "They have to make that connection that they're fighting for the same things."

The transit workers made that connection when they walked off the job amid a bitter dispute with the Metropolitan Transportation Authority over pensions and wages, shutting down New York's subway and bus system for three days and turning millions of people into pedestrians.

TWU President Roger Toussaint, responding to criticisms that the union was breaking a state law that bans strikes by public employees, invoked the name of civil rights icon Rosa Parks.

"There is a higher calling than the law and that's justice and equality. Had Rosa Parks answered the call of the law instead of the higher call of justice, many of us who are driving buses today would still be in the back of the bus," Toussaint said.

Union supporters brought up civil rights imagery, particularly when criticizing Mayor Michael Bloomberg for describing union leadership as acting "thuggishly," which they said was racist when used to refer to a predominantly minority union.

The Rev. Herb Daughtry, a longtime activist and influential black leader, said Bloomberg, Gov. George Pataki and Metropolitan Transportation Authority officials were in danger of being likened to "Bull" Connor, the segregationist police chief in Birmingham, Ala., who used fire hoses and dogs against civil rights marchers.

The Rev. Al Sharpton also weighed in with a civil rights struggle reference: "Martin Luther King Jr. was in Memphis to violate and defy a court injunction against a union strike when he was assassinated ... Would you call him a thug?"

Bloomberg said he stood by his characterization of the union leadership's actions, and his spokesman said it was "despicable to inject race into this situation." In contrast to his predecessor, Rudolph Giuliani, Bloomberg has gotten good marks for his relationships with the city's minority communities.

Despite the mayor's protest, race and economics are intertwined, and that is something unions recognize, said Dan Cornfield, labor and sociology professor at Vanderbilt University in Nashville, Tenn.

"Over the last 40 years, the degree of income inequality has increased, so we're an increasingly polarized society between haves and have-nots. The bottom half of the income distribution is increasingly and disproportionally racial and ethnic minorities, women and immigrants," he said.

Chaison pointed to the recent breakaway of some major unions from the AFL-CIO to form their own group. The unions that left tend to represent service workers, in fields like the textile, hotel, and restaurant industries, and have growing numbers of minorities as members.

"They see the labor movement as essentially that -- a movement -- a civil rights movement," he said. "They think this resonates with minorities and immigrants because it focuses on giving them a voice."