The Wisconsin Manufacturers and Commerce and Metropolitan Milwaukee Association of Commerce this week filed a lawsuit challenging recently enacted legislation that prohibits employers from discussing with employees whether to join unions.

Under 2009 Wisconsin Act 290 (SB 585), the Department of Workforce Development now requires employers to post in their workplaces a notice advising employees of their rights under the new law. Employers that violate the new law by discriminating against or retaliating against employees who refuse to attend meetings that discuss joining unions are liable for punitive and compensatory damages. Wisconsin is only the second state in the nation to pass such a law, joining Oregon.

In their lawsuit, WMC and MMAC argue that for over 60 years employers have had a federally protected right to hold mandatory meetings with employees to discuss the pros and cons of joining or supporting a union. Specifically, the business groups argue that Wisconsin’s new law unlawfully interferes with free speech under the First Amendment and is preempted by federal law.

The lawsuit was filed in the United States District Court, Eastern District of Wisconsin.