The court said it wasn't persuaded that ruling now would be an "appropriate exercise" of its discretion — despite a request for a special advisory opinion from Republican Gov. Rick Snyder in January.
Since Snyder's request, three lawsuits challenging the contentious law have been filed in state and federal courts. The law prohibits forcing public and private workers to pay union dues or fees as a condition of employment.
Snyder wanted the justices to especially decide whether the law applies to roughly 35,000 state employees who belong to unions and are under the authority of the Michigan Civil Service Commission. Contracts expire later this year.
"We're confident that the constitutionality and legality of the freedom to work laws will be upheld in the courts," Snyder spokeswoman Sara Wurfel said. "The goal in making this request to the Michigan Supreme Court was to bring that clarity to this public policy as quickly as possible and avoid protracted litigation. We respect the Supreme Court's decision and will continue to defend the freedom to work laws in the lower courts."
A separate union-led suit on whether the law applies to state employees is pending in the Michigan Court of Appeals.
An Ingham County judge is considering an "uphill" challenge — his words — that contends the law should be invalidated because demonstrators were locked out of the Capitol for hours while the measure was debated. And a federal judge in Detroit is overseeing a suit that argues the law shouldn't apply to private-sector workers because federal labor law regulates their rights.
Justice Stephen Markman, who had previously wanted to issue an advisory opinion, agreed on Friday that one shouldn't be given now. He cited a June brief from state Solicitor General John Bursch, who said while the Supreme Court should have intervened immediately at Snyder's behest, the issue is likely moot five months later because the state appeals court is expected to rule soon on the law's impact on state workers.
The right-to-work law passed the Republican-led Legislature in December and took effect in March over the objections of thousands of protesters at the Capitol. It made Michigan the 24th right-to-work state.
In making his request, Snyder hoped for a ruling before the court's term concludes at the end of July.
It's not the first time the Supreme Court has been asked to review a controversial law. In 2011, Snyder wanted the court to leapfrog lower courts and look at a law that placed emergency managers in distressed cities and school districts. The court didn't act before voters killed the law last fall.
The court did, however, agree to bypass the lower courts in 2011 to rule on the constitutionality of a law Snyder signed that lifted a tax exemption for pension income.