This decision by the Ninth Circuit Court of Appeals is a big legal win for labor.  In its decision, the full panel of the Ninth Circuit upheld a California law passed back in 2000 that prohibits recipients of state government funds from using it to oppose unionization of their employees (although they are free to use private funds to do so).

The right of states to control their own money might seem uncontroversial, but a lower federal court and then a three-judge panel of the Ninth Circuit both issued decisions striking down the law as preempted (i.e. incompatible with) the federal National Labor Relations Act.  The real danger was that states would be denied any ability to prevent public money being used to bust unions using those funds.

The legal details are embedded in the tortured precedents of federal labor law, but it gives you a sense of the anti-labor trend in the law that it was even a close call.  The Supreme Court may overturn the decision on appeal, but my gut says that that even the conservatives on the Court will end up upholding the Ninth Circuit's tight resolution of previous law. 

States and local governments hand out hundreds of billions of dollars in government contracts each year, so preserving the right of states to prevent those funds from being diverted into anti-union uses is clearly a big victory for the freedom to form unions.

Given that federal labor law changes have been continually filibustered by rightwing politicians over the years, state support of unions is one of the few avenues for effective political support for labor these days.  So any victory leaving state law options to support workers rights open is a reason to celebrate.