Organized labor is deeply worried about what happens after Tuesday.

By many measures, labor unions have been the Republicans’ fiercest, biggest-spending opponents in this year’s campaign, laying out more than $200 million in hopes of safeguarding the Democratic majorities in the House and Senate.

So it should be no surprise that Republicans, who appear to stand a good chance of winning control of the House, are signaling that they plan to push bills and strategies to undermine labor’s political clout and its ability to grow.

“Republicans are likely to pursue a version of what Samuel Gompers often said: ‘Reward your friends and punish your enemies,”’ said Joseph McCartin, a labor historian at Georgetown University.

One bill that is popular among Republicans would prohibit employers from agreeing to unionization through “card check,” a process often used today in which an employer recognizes a union as soon as a majority of workers sign pro-union cards — without holding a secret-ballot election. Another bill would severely crimp labor’s campaign spending by barring unions from using any portion of a union member’s dues for political purposes unless the member first gives written permission.

A Republican-led House or Senate is expected to be more eager than a Democratic-controlled one to approve free trade agreements that unions oppose, and to be more reluctant to enact stimulus plans that unions have supported, like the recent bill that gave states $26 billion to help save the jobs of teachers, police officers and other government employees. A Republican-controlled House or Senate would probably block a labor-backed bill that would give firefighters and police officers in every state the right to unionize.

“We fear that the Republicans are on the march, and that’s why we’re doing everything we can to stop them,” said Gerald McEntee, president of the American Federation of State, County and Municipal Employees, which is spending $91 million in the two-year campaign cycle.

McEntee praised the $26 billion jobs bill.

“That saved literally thousands of public-sector jobs,” he said. “I don’t think we’ll see something like that passed under John Boehner,” the Ohio Republican who is expected to become House speaker if the Republicans win control.

All this means that Republicans may well go on the offensive against labor, after two years in which unions have been on the offensive. Labor leaders have pressed their Democratic allies, unsuccessfully so far, to muster the 60 votes needed in the Senate to advance card-check legislation. Many Republican and business leaders say the card-check process is unfair because union organizers often pressure workers to sign the cards, an assertion that the unions deny.

“Most certainly, the issue of card check will be dead,” said Doug Heye, a spokesman for the Republican National Committee. “That will be a victory for businesses large and small.”

Heye said that many Republicans were likely to support legislation that would bar unions from spending members’ dues on politics unless members first “opted in.” Under current law, unions can spend a member’s dues on politics unless the member first opts out, a little-known procedure that few workers have followed.

Heye said when he visits campaigns around the country, union members who personally back Republicans had often complained that their unions were spending money to elect Democrats.

Union leaders vigorously oppose the opt-in idea.

“Obviously, this would further tilt the tables in favor of corporations in our political campaigns,” said Bill Samuel, the AFL-CIO’s legislative director. “Let’s hope the Republicans focus on putting people back to work, instead of taking away workers’ rights.”

If the Republicans win control of the House, Rep. John Kline, R-Minn., is expected to succeed George Miller, a Democrat from San Francisco, as chairman of the House Education and Labor Committee.

“One of the greatest threats to job creation is economic uncertainty,” Kline said in an e-mail after being asked about his plans should he become chairman. “The solution is to take economic threats — like tax hikes and card check — off the table and make the laws governing our workplaces more understandable, workable and effective for workers and employers.”

Kline is chief sponsor of the Secret Ballot Protection Act, a bill with 115 House co-sponsors that would bar employers from agreeing to unionization through card check. He has also criticized two policies that are favorites of construction unions: the Davis-Bacon Act, which requires that contractors on federal public works projects pay workers the prevailing wage, usually near the union wage, even if they are not unionized; and project labor agreements, which tend to tilt the awarding of federally-financed construction projects toward unionized contractors.

McCartin said, “I suspect the Republicans will target these policies by trying to make the case that they waste taxpayer money by promoting higher wages on projects that taxpayers pay for.”

Ronald E. Meisburg, a Republican and former general counsel for the National Labor Relations Board, predicted that if a Republican-controlled House cripples labor-backed legislative efforts to make it easier for workers to unionize, the Democratic-controlled labor board might take administrative steps. Meisburg, a lawyer at Proskauer Rose, noted that one Democratic labor-board member recently proposed making a change in the timing of workplace elections after employees file a petition to hold a unionization vote, reducing the delay to just five or 10 days. Unions want an accelerated schedule because they say employers have too much time to ply workers with anti-union propaganda, but employers complain that such quick elections would deny employers an adequate opportunity to campaign against unionizing.

“We’re concerned that the NLRB will do exactly that,” said Randel Johnson, senior vice president for labor matters at the U.S. Chamber of Commerce. “It would be unfair to hold elections before employers have a chance to state their case.”

Samuel predicted that labor could stop any Republican legislative offensive.

“When Republicans won control of the House in 1994, they tried to roll back 60 years of labor protections for workers, but we fought them to a stalemate,” he said. “If the Republicans attempt that again, I think this story will repeat itself.”

© 2010 The New York Times Company