U.S. Chamber of Commerce President Thomas Donohue vowed in a press conference Thursday morning that his business association would continue its battle against the Employee Free Choice Act.

“Labor unions and trial lawyers will expect payback,” Donohue said. “Their agendas should alarm every business, small and large.”

Donohue was adamant that the chamber would fight the Employee Free Choice Act, a pet cause of labor unions, who say it would allow workers the freedom to organize without company interference. Detractors say a voting system under the law would not be confidential, and would expose workers to threats and harassment.

The government “cannot rationally drop the Employee Free Choice Act on top of a stimulus plan,” added Donohue, referring to an expected effort to inject more money into the economy when Congress begins its lame-duck session on Nov. 17.

“The nation is well-prepared to address that subject and to participate in that debate, and it’s not gonna be a walk in the park,” he said, adding: “We’re going to win this thing.”

Donohue seemed encouraged that Obama had made it clear that fixing the economy is his first priority, but said the president-elect might find himself waging battles against members of his own party who are passionate about pushing certain issues forward.

He might spend “as much time debating within his own party as debating with the business community,” Donohue said.