As the fight over a unionization measure moves to the Senate, the business coalition trying to knock it down is following lawmakers home for the April recess with a six-figure radio and television blitz.

The group, called the Coalition for a Democratic Workplace, went up over the weekend with a television ad targeting Sen. Mary Landrieu (D-La.). That spot is set to air statewide, except in New Orleans, for several weeks. And the coalition today will launch radio ads in 12 Congressional districts, half thanking Members who voted against the measure and the others attacking those who supported it, said coalition spokesman Todd Harris.

Labor groups plan to answer the big business campaign over the break with local events aimed at moderate Senators from both parties who have yet to declare themselves on the issue, according to AFL-CIO legislative director Bill Samuel. And Americans United for Change, another group pushing the bill, will back up that effort by unveiling seven state-specific reports detailing the positive impact the measure would have on workers’ health care and pension benefits, a spokesman said.

But despite the heavy investment in the fight early on, advocates on both sides agree the measure is unlikely to become law this Congress, since Senate Republicans likely will mount a filibuster and President Bush has vowed to veto it. So what’s all the fuss about?

Business and labor operatives said they have their eyes on the next Congress, when Democrats are in a good position to expand their Senate majority and the party controlling the White House is up in the air.

While easily the most high-profile, the fight over the measure, dubbed the Employee Free Choice Act, is only one of many business lobbyists said they are waging in anticipation of even tougher times ahead.

With razor-thin margins in the Senate, corporate lobbyists said they feel confident they can marshal enough votes there to hold up many proposals that bite their bottom lines. A greater threat to some is what looms beyond this Congress. Republican Senators are defending 21 seats this cycle, while Democrats only have to protect 12.

And while they take solace in President Bush’s veto pen for the time being, some see Democrats riding momentum from the midterm elections and continued dissatisfaction with the Iraq War back into the White House in 2008.

“Our goal is not just to keep this bill from becoming law this year,” said Harris, with the business coalition. “We already think it won’t. Our goal is to make sure that it doesn’t get brought up again in 2008, 2009 or ever. Nobody should bet the farm on what the political landscape will look like in 2009 and not have at least some kind of insurance policy and laid the foundation in advance of that.”

Business lobbyists and Republican aides pointed to a slew of other items they are trying to drive a stake through this year so they don’t rear up down the line.

First up likely will be the Senate Democrats’ plan to give the government authority to negotiate prices with drug companies. The House already approved a measure as part of the Democrats’ “100 hours” agenda, and Finance Chairman Max Baucus (D-Mont.) has announced he wants to move quickly to follow suit after the break. While pharmaceutical industry lobbyists said they are not taking anything for granted this Congress, a Senate GOP aide said Republicans “are feeling confident” they can filibuster the bill. “Those who are involved with it want to ensure its defeat,” the aide said.

Small business lobbyists are working to deal early, decisive blows to measures expanding paid sick leave and family medical leave. Susan Eckerly, vice president of federal policy at the National Federation of Independent Business, said both have the potential to become “multiyear fights.” So her group is getting started now activating its membership and trying to pin down Senators from swing states.

“If you’re going to fight something in a future Congress, for a grass-roots group like ours, you have to educate your members first, and if they’re indeed fearful of what’s coming down the pike, they’ll raise it with their legislators,” she said.

Many other interests are training their focus on the tax-writing committees. With Democrats hunting for revenue offsets to help them meet their “pay-as-you-go budget” pledge, some with protected tax status fear they could get stuck with the bill in future years if they are even given the once-over this year.

“Once a revenue offset becomes available, it simply doesn’t go away,” said Jade West, a lobbyist with the National Association of Wholesaler-Distributors, who is leading a coalition to protect an asset valuation method called “last in, first out.”

“We think we’ve got the genie in the bottle this year, but we’re not letting our guard down,” she said. “Eternal vigilance is the price of liberty.”

Bill Miller, political director of the U.S. Chamber of Commerce, said the trick for business groups is not to allow lawmakers off the hook simply because certain measures won’t get signed into law this year. “You can’t allow Members to think these are free votes, because they won’t be in the future,” he said. “Members are pretty reluctant to change their voting patterns or behavior on the same issue. Once they’re defined, it becomes difficult to switch. That’s why you invest early.”

The unionization bill narrowly passed the House last month with a big push from organized labor. It was introduced in the Senate last week by Health, Education, Labor and Pensions Chairman Edward Kennedy (D-Mass.), though the schedule for action in that chamber is still unclear.

The measure would allow workers to unionize if a majority checked off their approval on cards circulated by union organizers. That method would replace the current system of federally supervised secret ballot elections, which labor officials and Democratic leaders argue subjects workers to intimidation by employers.

Business groups and many Republicans counter that the proposal would open the door for union leaders to strong-arm workers into signing up, undermining the democratic principle of voter privacy in the process.

The 30-second spot targeting Landrieu, who is up for re-election, emphasizes the point.

It opens with a shot of a voting booth. “This is a voting booth,” a female narrator says. “The curtain protects your privacy, your vote. Now special interests want Congress to rip that curtain away and make workers choose in public about joining a union.”

The coalition, which includes the Chamber, NFIB and the National Association of Manufacturers, also is paying for eight weeks of radio ads thanking Reps. Dan Boren (D-Okla.), Jo Ann Emerson (R-Mo.), Jim Gerlach (R-Pa.), Randy Kuhl (R-N.Y.), Candice Miller (R-Mich.) and Denny Rehberg (R-Mont.) for opposing the measure.

Spots criticizing those who supported it will run in the districts of Reps. Nancy Boyda (D-Kan.), Christopher Carney (D-Pa.), Tim Mahoney (D-Fla.), Thaddeus McCotter (R-Mich.), Tim Murphy (R-Pa.) and Heath Shuler (D-N.C.).