David E. Bonior is one politician organized labor knows it can trust. During his 26-year career on Capitol Hill, the one-time House Democratic whip never hesitated to use his leadership power on and off the floor to advance the interests of unions — even to the point of battling with his friends.

After a failed bid for governor of Michigan in 2002 that cut short his career in Congress, Bonior eschewed the usual post-lawmaker career path of K Street lobbyist, instead settling in as chairman of American Rights at Work, a Washington-based coordinating and research group focused on promoting union organizing efforts. But Barack Obama ’s election opened up a far more expansive range of opportunities for the veteran politician from Detroit’s suburbs. Bonior quickly signed up for duty on the president-elect’s economic transition team, while throwing cold water on early speculation that he would be an attractive name on the short list for secretary of Labor. He said he had “other things to do.”

What he had in mind became clear when he and other transition planners laid down the law to labor’s feuding factions to settle their differences and throw more weight behind the new president by speaking with one voice.

It was scarcely surprising that Bonior was the choice — with the White House’s tacit support — to heal the schism that opened in union ranks when seven dissenting unions split from the AFL-CIO in 2005. But it remains to be seen whether he can find a way to balance competing leadership ambitions and the differing perspectives of industrial unionists, service workers and white-collar professionals.

The idea behind the Bonior-led National Labor Coordinating Committee is to build a united front among more than 16 million union members to capitalize on a recent growth in membership and to reconfigure the traditional union model for a post-industrial, service-providing economy.

Not incidentally, a reunited labor movement might also advance an agenda that puts special emphasis on health care and stimulating the economy. Meanwhile, all of labor’s factions share the objective of passing the Employee Free Choice Act, the politically charged card-check bill that would rewrite labor relations laws to help unions add to their numbers.

Bringing Back Breakaway Groups

The key to Bonior’s peacemaking efforts may lie in finding a face-saving formula that would allow the seven breakaway unions of the Change to Win coalition to rejoin the AFL-CIO. The coalition walked out of the federation’s convention four years ago, complaining that President John J. Sweeney’s AFL-CIO was spending too much dues money on political action to the neglect of organizing workers. But Change to Win can point to only scant membership gains in its own ranks. And it has been torn by dissension, including a messy power struggle between the Service Employees International Union and UNITE HERE, which represents an alliance of the Union of Needletrades, Industrial and Textile Employees with the Hotel Employees and Restaurant Employees union.

Some influential voices in the AFL-CIO may now be pushing Sweeney, poised to retire after 14 years at the helm of his group, to take a hard line toward Change to Win. “When they left, they said one reason was because the AFL-CIO paid too much attention to politics,” said Mark Gaffney, a former Teamster who now heads the 600,000-member Michigan AFL-CIO. “Well, we won the presidency; we won a majority in the Senate; we won a majority in the House. We may even now have a filibuster-proof majority,” Gaffney said. “From my standpoint, Change to Win is meaningless.”

The breakaway group’s demands have included changing the AFL-CIO’s name to instituting a rotating presidency in a rebranded federation — both ideas not likely to sit well with Sweeney and his loyalists. At this point, the renegades appear to have little bargaining leverage.

Change to Win leaders have “very little to point to that couldn’t have been achieved if they had stayed in the federation,” said Gary N. Chaison, a labor expert at Clark University in Worcester, Mass. “Organizing is a factor of individual unions, not federations.” And, he said, SEIU President Andy Stern continues to be a lightning rod for criticism. “There has always been a lot of opposition to Andy Stern’s leadership and his ambitions,’’ Chaison said. “What is happening with UNITE HERE is a mess.”

While mediating these issues, Bonior must bear in mind that the White House’s stake in a successful outcome may be growing more urgent as Republicans sharpen their attacks on the deficit-widening costs of Obama’s domestic program and interest groups mobilize to torpedo elements of his health care initiative.

Having taken himself out of the running for Labor secretary early on, Bonior may need no more complicated incentive for this seemingly thankless task than a true believer’s stake in seeing organized labor emerge as a reinvigorated force in American social and political life. “It makes it easier, if we are unified, to get there,” said Bonior in discussing labor’s shared goals with the Obama administration.