Michigan’s highest tribunal denied Gov. Rick Snyder’s request that it review the state’s recently approved right-to-work law, saying only that “we are not persuaded that granting the request would be an appropriate exercise of the court’s discretion.”

Snyder had requested the court render an expedited ruling on the law’s  constitutionality as a preemptive measure after a series of lawsuits against it were filed. The governor had hoped the court’s conservative majority would have made some of the challenges moot.

The governor also wanted a ruling on whether the law applies to unionized public sector employees. Union leaders have argued the law does not apply to them because their members are under the Michigan Civil Service Commission’s authority. Those contracts are up for renegotiation later this year.

There are six lawsuits challenging the act, including two by labor coalitions. One alleges the Republican legislation violated open meeting laws to pass the bill. Another challenges the constitutionality of right-to-work laws themselves.

The governor’s office remains optimistic about the law’s future. “We’re confident that the constitutionality and legality of the freedom-to-work laws will be upheld in the courts,” Snyder spokeswoman Sara Wurfel told the Detroit Free Press.

Right-to-work laws prohibit union contracts from requiring that all company employees belong to a union or at least pay dues to one as a condition of employment.

A total of 24 states have them. In December, Michigan became the most recent to adopt one. As the historic home of the auto industry, the symbolism of the state adopting the law was a stinging defeat organized labor has sought to reverse.

For more on the resurgence of right-to-work laws, read my column from last month, “Big labor unprepared to battle new right-to-work laws.