As labor unions continue to push for speedy passage of the Employee Free Choice Act — the “card check” bill — they may run into an unexpected speed bump: Native American tribes.

The bill, which would make it easier for unions to organize, has created a potential way for Native Americans to receive an explicit carve-out that under federal labor law, tribes and the companies they operate would be treated as government entities and not commercial enterprises.

Labor unions want their prized bill to move without any potential changes that could slow down its passage.

Several tribes, along with the National Indian Gaming Association and the National Congress of American Indians, have been participating in conference calls on how to lobby the issue, according to several lobbyists who were on the calls.

NIGA did not return calls. NCAI officials were not available for comment.

“Ultimately, from the tribes’ perspective this is a matter of protecting tribal sovereignty,” said Larry Rosenthal, who represents several tribes at Letan Consulting. “The tribes believe that they should be treated the same as federal, local and state governments that are exempted from the” National Labor Relations Act.

Chairman Robert Martin of the Morongo Band of Mission Indians in California agrees. “We’re not anti-union, but we want to make sure that tribal sovereignty is set in stone and not eroded,” Martin said.

The issue of tribal sovereignty came to a head in 2007 after a three-judge panel from the U.S. Court of Appeals for the District of Columbia found that Native American tribes must comply with federal labor laws.

Native American tribes are not explicitly mentioned in the National Labor Relations Act, the 1935 federal law that protects the rights of most private sector workers to organize unions and take part in strikes.

The appeals court case stemmed from a 1999 complaint by the Hotel Employees and Restaurant Employees International Union, alleging that the San Manuel tribe denied its organizers equal access to casino workers, while at the same time cooperating with the rival Communication Workers of America. The tribe and the CWA eventually agreed to a contract.

In making its ruling, the panel of judges determined that the San Manuel tribe operated its casino as a commercial enterprise, not a government entity.

“The National Labor Relations Board really overstepped their authority,” said former Sen. Ben Nighthorse Campbell (R-Colo.), referring to the five-member board that appealed the case to the federal court. “In almost all other endeavors, tribes are treated like states,” added Campbell, who lobbies for several Indian tribes and the National Indian Gaming Association at Holland & Knight.

But getting Congress to act could be tough. Stand-alone legislation to amend the NLRA has been introduced before. In 2004, former Rep. J.D. Hayworth (R-Ariz.) sponsored legislation to ensure that tribes were not considered commercial employers under the act. In the 110th Congress, Rep. John Kline (R-Minn.) followed suit. Both bills languished at the subcommittee level.

Native American lobbyists are realistic that getting language inserted will be an uphill battle against organized labor.

“We are looking at this as a vehicle for maybe changing that [court] ruling,” said Virginia Boylan, a lobbyist who specializes in Native American issues at Drinker Biddle & Reath. “Our people are talking to Members of Congress, … but our friends and their friends are the same.”

Indeed, Indian tribes’ lobbyists realize they are in a difficult position, since they are asking lawmakers to pit organized labor against Native Americans.

“This is a real tough vote for a lot of Members of Congress who want to be supportive of labor, but do embrace tribal governments as sovereign entities,” said James Wise, a lobbyist who represents several tribes at the government relations firm PACE.

There is likely to be more support for the tribes on the Democratic side than on the Republican side, according to Campbell.

“I don’t know how it will fall out, but I think the Democrats owe labor more than they owe tribes,” Campbell said. “More than likely they are doing labor’s bidding and will try to get this passed.”