Daniel DiSalvo explains at National Review Online what’s at stake in a major U.S. Supreme Court case heard Wednesday.

… [T]he Supreme Court will decide whether public-sector unionism violates the First Amendment rights of workers who refuse to join unions. The case will be one of America’s most consequential for government labor–management relations. If the Court rules for the plaintiffs, state- and local-government workers in 22 states will no longer have to subsidize organized labor as a condition of employment; instead, they will be free to choose the organizations to which to contribute money, or to contribute not at all. Janus thus affords the Court an opportunity to reinstate workers’ rights to free speech and association, and to restore some political balance by preventing public-employee unions from using money forcibly pried from workers opposed to or unenthusiastic about their agenda.

If it rules this way, the Supreme Court would overturn a 40-year-old precedent, Abood v. Detroit Federation of Teachers. Most observers think that the justices will do it: Janus marks the fourth time in five years that the Court has accepted a case about the constitutionality of public-sector unionism. The spate of recent cases, on this view, reflects the conservative majority’s desire to overturn Abood. Perusal of the Court’s jurisprudence going back to the 1950s shows that it has long struggled to determine the constitutionality of various laws that encourage unionism in the private as well as the public sector. Constitutional history also underscores the conundrums created by importing private-sector labor practices into a government setting.