Trade unions representing workers who stand to benefit from thousands of new construction jobs from the Keystone XL pipeline are furious at other unions that joined environmentalists in opposing the project.
AFL-CIO leaders hope to smooth tensions at their executive council's annual winter meeting that starts Monday in Orlando, Fla.
The issue reflects a decades-old conflict between union leaders who believe creating jobs is paramount and others who are more strongly aligned with progressive groups on environmental and social causes.
After the White House blocked the pipeline in January, Laborers union president Terry O'Sullivan said he was "repulsed by some of our supposed brothers and sisters lining up with job killers like the Sierra Club and the Natural Resources Defense Council to destroy the lives of working men and women."
His harsh words were directed at groups such as the Transport Workers Union and the Amalgamated Transit Union, which said the risk of possible oils spills and environmental contamination outweighed the benefit of new jobs.
Several larger unions, including the Communications Workers and Auto Workers, also jumped in with praise for Obama, agreeing with his administration's arguments that a quick deadline forced by Republicans didn't provide enough time for a fair review.
O'Sullivan was livid that unions whose members had no jobs to gain or lose from the project would make their opposition public while construction unions struggling with 17 percent unemployment in the industry are desperate for any jobs.
The split led the AFL-CIO to take no public position on the pipeline. Leaders are expected to discuss the need for solidarity and how to tone down tensions when unions can't agree.
"I think discussion is always good," said Larry Cohen, the Communications Workers' president. "You have to treat disagreements with respect. You have to work hard for unity."
Cohen has no regrets about siding with Obama. He said his union was not specifically against the pipeline, but merely opposed to the Republican "ultimatum" to shorten the timeline. He sees room for unions to disagree, especially in areas he doesn't consider central to the labor movement's core philosophy.
"On the issues that make or break the labor movement, I don't think the pipeline is one of them," he said. "We think the core of the movement is bargaining and organizing rights."
O'Sullivan has a different perspective.
"If there's legislation or a project that's good for another union, and my members don't have equity in the work, I'm going to be supportive or I'm going to say nothing," he said.
Republicans have pounded Obama on the pipeline issue, saying it's a question of whether the president wants to create jobs and reduce reliance on oil from the Middle East.
In the GOP's weekly radio and Internet address Saturday, North Dakota Gov. Jack Dalrymple called rejection of the pipeline an example of the administration "killing energy development with overly burdensome regulations."
The pipeline operator, Calgary-based TransCanada, said last month it would build a portion of the pipeline from Oklahoma to Texas. That 485-mile line from Cushing, Okla., to Port Arthur, Texas, does not require presidential approval because it does not cross a U.S. border.
The proposed 1,700-mile pipeline would carry tar sands oil from western Canada to refineries along the Texas Gulf Coast. The company expected to be ready in a few weeks to submit plans for a new route that avoids the environmentally sensitive Nebraska Sandhills region and an aquifer that is a key water source for eight states.
It's hardly the first time unions have disagreed with each other.
Union officials say there are bound to be conflicts among the labor federation's 57 member unions. The pipeline split is just one of more than a dozen topics that will come up in Orlando.
Generally, there is broad support for endorsing Obama for a second term and working to fend off anti-union legislation in Ohio, Wisconsin and other states. Unions are working together to recall Gov. Scott Walker, R-Wis., who led the drive to pass legislation that curbed collective bargaining rights for many of the state's public employees.
A big issue this election year is how the AFL-CIO focuses its political apparatus and money to help Obama win and boost Democrats in their efforts to regain control of the House and keep their majority in the Senate.
Obama campaign manager Jim Messina will attend the meeting as union presidents and their political operatives consider how much to spend on campaign advertising, phone banks and door-to-door efforts that traditionally benefit Democratic candidates.
"Repositioning" the labor movement and improving the image of unions also are on the agenda as leaders experiment with new organizing techniques and try to attract more public support in their fight with critics trying to limit their clout in state legislatures.
The AFL-CIO has spent about $1.5 million this year on a "Work Connects Us All" television ad campaign in three cities. Union leaders are considering whether to expand the campaign, which also includes a new website.
"We need to get out the message that we're all in this together," said United Steelworkers president Leo Gerard. "There's a reason the right wing is attacking the hell out of the labor movement. We're effective in speaking for the 99 percent and the right wing doesn't like that."