Unite Here Local 355 approached Mardi Gras Gaming, owner of a Florida dog track and gambling casino, in 2004 with a proposition: It would run ads in favor of a local gambling ballot initiative the company wanted to pass. In exchange, the company would make it as easy as possible for the union to organize its workers.

To further sweeten the deal, Unite Here promised "labor peace" to the company. In other words, it vowed not to strike, protest, picket or otherwise disrupt the company's business. It was a win-win deal for everyone — except the employees.

Last week, the Supreme Court announced that it would take up the case of Unite Here Local 355 v. Mulhall. In its own way, this case may be as important as the Voting Right Act or gay-marriage decisions. It could potentially hobble a major union organizing practice: striking deals with management before they try to organize workers.

The case specifically deals with the question of what constitutes a bribe or similar inducement in labor union organizing cases. Can it extend to something non-monetary, like employee contact information? That's what the 11th Circuit Court of Appeals ruled.

Unions were eager to appeal that ruling. "The theory is implausible on its face. No employer would think to bribe a union by making it easier for the union to organize," Unite Here said in a statement last week.

Well, an employer might if the deal was as sweet as the one Unite Here struck with Mardi Gras Gaming. And that's why the case is important.

The classic image of workplace organizing from movies like Norma Rae is of an up-from-the-grassroots effort by ordinary people. But a lot of organizing is done in the opposite way: with outside labor organizers striking "top down" deals with the management first, then trying to get the workers on board. Unite Here has used it in dozens of cases involving casinos.

The union's deal with Mardi Gras required the company to turn over employee contact information, allow union officials onto company property and not counter the union's effort to organize its workplace in any way. Employees would only hear what the union told them without anyone from the company to contradict them.

Once the union claimed it had a majority of employees signed up, Mardi Gras would then waive its right to contest the election to the National Labor Relations Board.

This wasn't a bad deal for Mardi Gras. Its workers might get unionized but the union wouldn't be able to strike, giving the company plenty of leverage in contract negotiations.

Martin Mulhall, a 40-year Mardi Gras employee, realized he could wake up one morning to find he suddenly was represented by a union that wouldn't do much for him. With the help of the National Right to Work Legal Defense Foundation, he challenged the deal.

The Appeals Court ruled that the employee contact list Unite Here got constituted a "thing of value" to the union and therefore violated the anti-bribery sections of federal labor law.

This was a novel reading of the law. The dissenting judge wrote: "Even if the union has some other aim besides achieving collective bargaining rights (such as obtaining more members and dues without ever promoting the interest of the employees), such conduct implicates the union's duty to its members, not the collective bargaining process between the employer and the union."

In others words, it may be wrong but it isn't illegal. That is essentially the position of Unite Here too.

"The aspects of the agreement attacked by Mulhall ... have been regular features of labor relations since Taft-Hartley was passed (in 1947)," it said. To change this now would "wreak havoc" with labor law.

The Supreme Court will now determine whose interest the collective bargaining process is meant to promote: the workers' or the union's.